In 2013, 21 schools, colleges, businesses and shopping centres across the country received mysterious envelopes containing an ominous white powder. 

Some of the envelopes contained letters with threats such as "if I was you I would hold my breath and run in the name of Allah” and were signed off with the ISIS black flag. 

Two primary schools and multiple shopping centres were evacuated over fears of a potential biological or chemical attack, though the white substance turned out to be talcum powder. 

The plot thickened when DNA found on the letters was matched to an unidentified man who had carried out a horrific knifepoint sex attack in Rainham in 1988. 

A search for the mystery man which lasted almost a decade would eventually culminate in the suspect driving at 100mph down the motorway while waving an imitation handgun out the window and wearing a mock suicide vest.

On Tuesday (March 26), the full details of this case were revealed publicly when terror hoaxer and sex attacker Gary Preston appeared in court after he pleaded guilty to 21 terror charges and the 1988 indecent assault.   

Surrey Comet: 'Warped' individual Gary Preston, a white non-Muslim, sent the envelopes as he wanted to cause fear and panic'Warped' individual Gary Preston, a white non-Muslim, sent the envelopes as he wanted to cause fear and panic (Image: ERSOU)

‘Run in the name of Allah’  

Over the course of six weeks in 2013 a total of 21 envelopes were sent to schools, shopping centres and businesses across the country, prosecutor Maryam Syed told the court. 

They contained a white powder – talcum powder – which the sender had intended would be mistaken as a deadly poison, possibly ricin. 

Some of the envelopes contained letters with threats such as “if I was you I would hold my breath and run in the name of Allah”, “think fast, you have seconds inshallah”, “there are improvised explosive devices planted” and “we have hostages and any attempts to rescue they will meet their fate”.    

The letters ended with sections of Arabic text and a symbol recognisable as the ISIS black flag. 

The targets included primary schools in Braintree, Essex - Lyons Hall Primary School and St Michael's Church of England Primary School.  

“The white powder was immediately assumed to be a very dangerous chemical,” Ms Syed said.  

“The concern and fear of the people who opened the letters was not just for workers and themselves, but also for the children.”  

Letters were also sent to Braintree College, Notley High School and various businesses in Braintree including Costa Coffee, Specsavers, Barclays, Coral bookmakers and Freeport Shopping Centre.  

Both Westfield shopping centres in London also received letters, as did the DVLA headquarters in Swansea, Transport for London, Anglia Ruskin University, Elmsleigh Shopping Centre in Staines, Bishop’s Stortford Post Office and a Premier Inn near Stansted Airport. 

Surrey Comet: One of the envelopes was sent to Westfield StratfordOne of the envelopes was sent to Westfield Stratford (Image: PA)

Linked to a 1988 cold case 

Though most of the addresses were printed and stuck on envelopes, several had been written by hand and DNA was found. 

Officers from the Eastern Region Special Operations Unit (ERSOU) who oversaw the counter-terror investigation checked DNA against the police database and found it matched an unidentified individual who had sexually assaulted a woman in 1988.  

At around 8am on a morning in January 1988, a lady in her 20s entered the women’s public toilets in Cherry Tree Lane in Rainham while her husband waited outside in a car, prosecutor Ms Syed said. 

As she walked out of a cubicle she was grabbed by the throat from behind and a knife was forced against her neck.  

Ms Syed told the court: “She was dragged back into the cubicle where she was confronted by a white male wearing a cotton balaclava. He told her ‘Pull up your jumper or I’ll cut your throat’.” 

The woman was sexually assaulted by the man, who then told her to wait in the toilets for five minutes and left. 

She left the toilet and went to her husband who tried to chase after the attacker but he could not catch up. 

Despite semen stains from the woman’s clothes being sent for analysis, the perpetrator was never found. 

Surrey Comet: Preston escaped justice for the Cherry Tree Lane attack for over three decadesPreston escaped justice for the Cherry Tree Lane attack for over three decades (Image: Street view)

‘I’ve always been a joker’ 

While officers had linked the bomb hoaxer to the 1988 sexual assault, they were not able to identify a suspect. 

But a series of incidents in 2020 led police to believe that their mystery man was 65-year-old Preston, a white non-Muslim from Haverhill in Suffolk. 

In summer 2020 Preston phoned the fire brigade and told them he had taken a deadly substance called ricin. 

Then one of Preston’s relatives later reported taking “toxic plants” away from him. 

Preston's previous convictions included two sexual offences, as he had exposed his penis to a woman from the window of his house in 1979 and to a woman in a pub in Rainham in 1982.

At 6.50am on September 16, 2020, Preston was arrested on suspicion of 21 terror offences and indecent assault. 

When he was interviewed by police he told them he suffered from dementia. 

“In short, he said that he’s always been a joker but he didn’t recall sending the letters and didn’t know what the powder was,” Ms Syed said. 

Preston was released under investigation. 

‘100mph with a gun waving out the window’ 

At around 7.30am on December 29, 2021, customers at a service station on the A1307 in Cambridgeshire noticed a handgun lying on the forecourt. 

Preston was seen standing near the gun, waving to staff members at the petrol station. 

“He then entered the shop and through apparent tears he told staff he had no money to pay for fuel he had just drawn,” Ms Syed said. 

“He referred to himself as a police officer, but then told them he worked for the military.” 

When one of the staff went outside to take a photo of Preston’s registration number, Preston picked up the gun and said it’s not real so there’s nothing to worry about. 

After going through the non-payment process Preston drove off, leaving behind nine bullets. 

Police were called at 8.23am and officers from Essex Police managed to track Preston to the A414. 

Preston was driving at 100mph while holding the gun out the window, swerving across lanes and narrowly avoiding crashes, Ms Syed told the court. 

When police brought Preston to a stop they saw he was wearing what appeared to be a C4 explosive attached to a black vest. 

But when police handled the ‘C4’ it was revealed to be a block of wood wrapped in plastic. 

As well as the imitation handgun and explosives, Preston also had a hunting knife in his car. 

“During the incident he repeatedly indicated that he wanted police to kill him,” Ms Syed said. 

Brought to justice 

Preston pleaded guilty to offences including dangerous driving and possession of an imitation firearm and last February he was jailed for three years and four months.

After he was detained in HMP Chelmsford, Preston appeared at Woolwich Crown Court in August 2023 where he pleaded guilty to 21 charges brought under anti-terror laws. 

He admitted to sending 21 envelopes “with the intention of inducing in a person a belief that it is likely to be, or contain, a noxious substance or other noxious thing and thereby endanger human life or create a serious risk to human health”. 

Targeting schools illustrated his "warped mindset", the head of ERSOU’s counter terrorism unit said at the time.

Then three months later at Snaresbrook Crown Court he pleaded guilty to indecent assault and possession of an offensive weapon. 

Both of these charges related to the 1988 sexual assault in Rainham, meaning he was finally convicted 35 years after the attack took place. 

Surrey Comet: Preston appeared at Woolwich Crown Court via videolink from HMP ChelmsfordPreston appeared at Woolwich Crown Court via videolink from HMP Chelmsford (Image: PA)On Tuesday (March 26) Preston appeared at Woolwich Crown Court via videolink from HMP Chelmsford to be sentenced for the terror offences and 1988 indecent assault. 

Preston was in a wheelchair and is said to be suffering from HIV, for which he refuses to take medication. 

Prosecutor Ms Syed said Preston has not been entirely truthful about his medical conditions and appears to “malinger and exaggerate” his symptoms. 

Defending Preston, barrister Steven Dyble said no mental health issues could be offered as mitigation for his behaviour. 

“He is undoubtedly responsible for the decisions he took,” Mr Dyble said. 

But he added that Preston is suffering “cognitive decline” and maintains that he has no recollection of any of the events he’s been found guilty of. 

After hearing the facts of the case and Preston’s mitigation a judge adjourned sentencing until April, warning Preston that he probably faces a lengthy prison sentence for these offences.