A man has been jailed for more than four years after targeting schools, shopping centres and businesses in a hoax terrorism campaign.

Gary Preston, 64, sent envelopes containing white powder and threatening letters that caused panic and evacuations at some of the venues over a six-week period in 2013.

He was sentenced to four years and three months in prison at Woolwich Crown Court on Thursday, after previously pleading guilty to 21 charges of sending a hoax substance contrary to the Anti-Terrorism, Crime and Security Act 2001.

The court heard that Preston sent 42 envelopes containing white powder, which was later confirmed to be talcum powder, from September 20 to November 4 2013.

Among the venues targeted were the Westfield shopping centres in both east and west London, schools and colleges in Braintree, Essex, and the Premier Inn at Stansted Airport.

The venue addresses were either printed out and stuck onto the envelopes or handwritten in black ink.

Some of the envelopes also contained threatening letters on white paper that included small texts of Arabic, such as “Think fast, you have seconds Inshallah”.

One of the envelopes caused an entire hotel with 303 rooms to be evacuated, the court heard.

Preston was arrested on September 16 2020 and pleaded guilty to the charges on August 11 last year.

The defendant was also sentenced to a further five years and three months in prison for a separate charge of serious indecent assault at knifepoint that occurred on January 26 1988 at a women’s public toilets in Rainham, Essex.

Defence barrister Steven Dyble said at an earlier hearing that Preston had suffered “a cognitive decline” in recent years but added: “There are no mental issues that we seek to lay before the court.

“He is undoubtedly responsible for the decisions that he took.”

Preston, who appeared in court via a video link from HMP Chelmsford, spoke only to confirm his identity before the sentence was handed down.

Judge Andrew Lees said the respective sentences were to be served consecutively, giving Preston a total sentence of nine years and six months in prison.

The judge added there was “a significant risk” of the defendant “committing further specified offences” which was an aggravating factor in the sentence.

Hannah Wilkinson of the Eastern Region Special Operations Unit (ERSOU) said: “By targeting places such as primary schools and airports, there’s no doubt that Preston had set out to cause as much distress and worry as he could.

“It is also clear that, by sending these packages to more than 20 organisations across the country, he had spent significant time planning and attempting to cover his tracks.

“It’s a positive outcome that Preston will now spend a significant spell behind bars.”