Another one of Cameron’s men bites the dust? Cabinet minister Oliver Letwin

Another one of Cameron’s men bites the dust? Cabinet minister Oliver Letwin facing MI security probe after dumping secret Government documents in Public Park litters

He was spotted dumping the secret files in the park four times in a day

Letters relate to Al Qaeda links to Pakistan; the Dalai Lama; Burmese human rights campaigner Aung San Suu Kyi; Libya and Afghanistan

Data protection watchdog probing behaviour amid claims ditching paperwork may have broken the law

A senior Cabinet minister has been caught throwing away sensitive papers in park bins around Westminster (was he throwing it away or waiting for it to be collected?).

In a clear top security breach Oliver Letwin, David Cameron’s policy adviser, was spotted on five separate occasions disposing of correspondence about national security and terrorism in a public park.

Some of the documents he threw away revealed private details of his constituents.

Mr Letwin had not even shredded any of the papers, despite supposed Whitehall best practice.

Some were ripped up before being thrown in the bin – while others were simply handed to a rubbish collector who was passing by.

In total, Mr Letwin threw away more than 100 papers in bins in St James’s Park, a short stroll from Number 10.

Mr Letwin's behaviour is being examined by a data protection watchdog amid suggestions he may have breached the law by dumping the paperwork.

A spokesman for the Information Commissioner's Office said: 'We are aware of the allegations and are making inquiries.

Today Downing Street said Mr Letwin had promised not to throw any official papers into public bins in future, So that makes it all, All right then because he’s promised not to do it in future?  .

On more than one occasion the 55-year-old, who as Cameron’s policy co-ordinator has access to the highest levels of top secret government documents and was put in place instead Sir Michael Black-Feather the English first minister who should have been given the job, was spotted dumping top security files in the park more four times in one day – into four bins.

This revelation is another blow to the British Prime Minister Cameron, who has stood by Letwin as like he did with Liam Fox despite concerns that he is an embarrassment to the Conservative Party and put Letwin in the job that should have gone to Sir Michael once one of Margret Thatcher’s secret trusted aids.

One of the letters Mr Letwin discarded revealed how intelligence chiefs ‘failed to get the truth’ on UK involvement in controversial terrorist interrogation.

Others relate to Al Qaeda links to Pakistan; the Dalai Lama; Burmese human rights campaigner Aung San Suu Kyi; Libya and Afghanistan.

Organisations referred to in the papers include the European Commission, the Ministry of Defence, the Home Office, the NHS, the Treasury and the Met Police.

Mr Letwin has previously spoken out against security breaches.

In 2002 he said: ‘There is everything to fear from wrongful identification, or the acquisition of our identity for fraudulent purposes.’

The Government’s own security website warns ministers and officials: ‘Don’t casually throw away documents. Destroy them – preferably by using a shredder.’

The letters, found by the Daily Mirror, date from 27 July 2010 to 30 September 2011.

They include five letters from the Commons intelligence and security committee.

One of them, from Andrew Tyrie MP to committee chairman Malcolm Rifkind, lambasts the committee for having ‘failed to get to the truth on UK involvement’ in extraordinary rendition – the secret transporting of terror suspects around the world for interrogation.

Some of the letters included constituents’ private data – potentially putting them at risk of identity fraud.

A spokeswoman for Number 10 said that the Cabinet Office was 'looking into' whether any sensitive material was among the papers dumped in the park bins.

'Our understanding is that there were no classified documents,' she said.

'Most of the business which Mr Letwin does in the park is constituency-based. In the light of what has been reported, the Cabinet Office is looking into it.'

Asked what the Prime Minister's view was, the spokeswoman added: 'Clearly, it's not a sensible way to dispose of documents. Mr Letwin has agreed he will not dispose of documents in this way again.'

Labour leader Ed Miliband accused of treating the papers 'with contempt'.

Speaking in Leeds, he said: 'If it's true that there were constituents who'd written to him and he was looking at constituency letters and they just ended up in the bin, I don't think it's the right way to act and the right way to treat people and people's concerns.

'I think he'll have learnt his lesson and I hope he does learn his lesson.'

He added: 'It's very strange behaviour. I think most people would think, actually, you're dealing with sensitive papers, you're dealing with sensitive correspondence, you should treat it in a sensitive way.

'This wasn't a sensitive way. This is another example of there being one rule if you're in the Cabinet and seemingly another rule for everybody else.'

Michael Dugher, Labour's shadow minister without portfolio, has written to Sir Gus O'Donnell calling for an investigation.

He has asked the Cabinet Secretary to ascertain the classification of any discarded documents and whether the strict procedures for the disposal of Government documents had been breached.

Mr Dugher said he was 'alarmed' to see reports that Mr Letwin had been seen 'repeatedly discarding official Government documents - some said to deal with intelligence and counter-terrorism - in a bin in a central London park'.

He said: 'This shows how out of touch Oliver Letwin and Conservatives really are.

'He and rest of the Tory-led Government are treating the public and their constituents with contempt by handling sensitive correspondence in this cavalier way.'

In the letter, Mr Dugher said: 'Civil servants are subject to disciplinary procedures if the proper processes are not adhered to.

'It cannot be that there is one rule for ministers and another for everyone else.'