A man who claims he was forcibly returned to Libya with the help of British authorities said he is disappointed at the news no-one is to be charged following a four-year investigation.

Despite being presented with more than 28,000 pages of evidence by police looking at whether officials in Britain were complicit in the rendition of two families who were unlawfully detained in Libya, the Crown Prosecution Service said there is "insufficient" evidence to charge anyone.

Abdel Hakim Belhadj and Sami al-Saadi, along with members of their families, were kidnapped and sent to face punishment in Libya in 2004.

Mr Belhadj, a key military figure in the uprising that toppled dictator Muammar Gaddafi, was living in exile in Beijing, China, but was detained with his wife en route to the UK where they were trying to seek asylum.

He accused former foreign secretary Jack Straw and an ex-senior MI6 officer, Sir Mark Allen, of being responsible for his rendition, alongside his pregnant wife, from Thailand to Libya.

Following the CPS announcement Mr Belhadj told the BBC: "I am very disappointed that individuals responsible will not be prosecuted. If there is political interference with the courts then it undermines British justice."

Sue Hemming, head of the CPS's Special Crime and Counter Terrorism Division, said: "Following a thorough investigation, the CPS has decided that there is insufficient evidence to charge the suspect with any criminal offence.

"We made our decision based upon all the available admissible evidence and after weighing up all of the information we have been provided with."

The Metropolitan Police, who had worked on the probe named Operation Lydd since it began in 2012, said a specialist team of detectives had conducted a "thorough and penetrating investigation".

In a statement they said: "A comprehensive file of evidence in excess of 28,000 pages was presented to the CPS on 12 June 2014. Subsequent to that submission a number of additional documents have been provided in response to CPS requests.

"It is entirely a matter for the CPS to decide on whether a case goes forward to prosecution. They have now concluded that there is insufficient evidence to provide a realistic prospect of conviction against any individual in this matter."