The defence lawyer for a man who was falsely accused of sexually assaulting a well-known actress has claimed CCTV footage was slowed down by prosecutors.

Mark Pearson, a 51-year-old artist, was accused of sexually assaulting a well-known actress in her 60s when their paths crossed at London's Waterloo station.

Last month a jury cleared him of 'sexually penetrating' the woman, who cannot be named for legal reasons.

The jury unanimously dismissed the prosecution claim that the crime could have occurred in just a split second in front of dozens of commuters.

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CCTV showed Mark Pearson, a 51-year-old artist, walking through Waterloo was on his way home from work, weaving through a thick tide of London commuters and carrying a paper in his left hand

It has now been alleged that the CPS slowed down the CCTV footage of the station in an attempt to bolster their case.

Mark Bagshaw, Mr Pearson's defence lawyer, told The Telegraph: 'The CCTV was served on us in a way in which had been altered.

'The few seconds when my client walked past the alleged victim had been slowed down so it looked like he had more time to commit the alleged actions than he in reality did have.'

The CPS's alleged actions meant Mr Pearson's lawyers had to hire a forensic expert to correct the video.

Walking towards him across the concourse came an award-winning star of film, TV, theatre and radio

It cannot be said with certainty that the artist and the actress made even fleeting physical contact. CCTV images showed only that they walked past each other

He then walks on, having passed her for no longer than one second. Yet the woman, who is in her 60s, claimed Mr Pearson sexually assaulted her – penetratively – for 'two or three seconds'

By reducing the video's speed by half, the moments before and after Mr Pearson passed the woman, would have seemed longer to the jury than they really were.

The lawyer added: 'If we had not taken the steps we had, the CCTV would have been presented to the jury at that amended speed.'

Mr Pearson was cleared of the charge by a jury in 90 minutes at Blackfriars Crown Court.

Today he appeared on ITV's This Morning where he described the trauma the case had caused him.

He said: 'The footage totally contradicts what she was saying.

'I hold the CPS more responsible because we had the CCTV footage analysed by an expert, and the CPS still proceeded with the trial.

'There is something that has gone radically wrong with their processes.'

A CPS spokesman said: 'There was sufficient evidence for this case to proceed to court and progress to trial. We respect the decision of the jury.'

Mr Pearson (pictured on This Morning ) says he feels as though he has undergone a form of mental torture

The defence team questioned in court how Mr Pearson could have carried out the alleged assault when he was carrying a newspaper in one hand and holding his bag with the other.

Mr Pearson told the court: 'I would have had to crouch down, put my hand up the woman's skirt... penetrate her, take my hand out again... all while holding the newspaper and walking along the concourse... It's preposterous... It is against everything I believe in as a human being. I did nothing.'

There were no witnesses and no forensic evidence. The actress failed to pick out Mr Pearson in an identity parade of video images.

Summing up the case, the judge, His Honour Peter Clarke QC, told the jury that to convict Mr Pearson they had to be sure the assault happened as the actress described. There could be 'no middle ground'.

Every day, 300,000 people flow through Waterloo in Central London – Britain's busiest station. 'I was just one of those commuters – in the wrong place at one moment in time,' Mr Pearson added.

'For me, half a second turned into a year of hell. I feel I have undergone a form of mental torture sanctioned by the state.'