In his appeal, Mr Blackman condemned the findings as ‘arbitrary and draconian’ and designed to generate a ‘good headline for Ipsa’.

He stressed he had apologised for £82.80 of travel to party political events, and was ‘extremely reluctantly’ ready to repay £97.65 for party political journeys even though Mr Davis had not ‘properly evaluated’ the situation.

He said he would return another £56.70 for home to office travel because he could not produce ‘detailed evidence’ to support it.

But Mr Blackman made clear he did not accept criticism of the distances he had claimed for. ‘I absolutely maintain that these routes are the most cost effective possible based on local traffic conditions and the need to ensure that journeys are of a predictable duration to arrive at the appointed time,’ he said.

‘My claims are provably compliant with the scheme so therefore you should withdraw your damaging and entirely unwarranted allegations at this juncture.

‘I understand that, having embarked on and publicly announced this investigation, it is in your personal interest to back up this decision with findings of wrongdoing that will generate a good headline for Ipsa.

‘Therefore I am sorry to report that I will absolutely be maintaining my innocence in this matter to my constituents, to the (Commons) Commission and on the floor of the House if necessary.’

Last month’s provisional report from Mr Davis revealed that Ipsa officials wrote to Mr Blackman in October 2011 voicing concern that he was putting in for ‘around twice the average for constituency mileage across the UK and some six times higher than other suburban London area constituencies where mileage is claimed’.

The watchdog triggered an initial investigation by its compliance officer in December 2012, with Mr Blackman being told: ‘A comparison of your claims against the distances quoted by Google Maps would suggest a pattern of over-claiming. On average, your claims are almost twice the distance shown on Google Maps and in some cases significantly more.’

A two-mile journey from his home to Harrow Weald had been claimed as 10 miles, while a five-mile return trip to Stanmore was filed as 15 miles.

After a discussion with Mr Blackman, Mr Davis declined to launch a full-blown investigation, instead deciding the issue could be dealt with through ‘support and advice from Ipsa to ensure the MP improved his record-keeping’.

However, an audit in 2013-14 found that Mr Blackman had again racked up the highest mileage of any MP.

He claimed more than 400 miles per square mile of his constituency, almost double the average for the next 10 highest-claiming MPs.

A 33-mile return journey to the new Tottenham Hotspur training ground in Enfield was claimed as 54 miles – although the MP later admitted this was a mistake and the figure should have been 39 miles.

The compliance officer this time launched a formal probe – but only looked at claims made after his meeting with the MP in January 2013.

He found that Mr Blackman had merely reduced standard claims for regular journeys by a single mile – for example, saying he drove 14 miles to Stanmore rather than 15.

During the investigation, Mr Blackman attempted to explain apparently standard claims for journeys to areas of his constituency by arguing that he was using ‘average’ distances.

But Mr Davis said that ‘conflicted with other statements that journeys were dependent on the traffic conditions pertaining at the time of travel’.

He also rejected a suggestion from Mr Blackman that he was using local knowledge to avoid traffic and find the quickest rather than shortest routes – ‘if this were the case then journeys would show distinct variations’.

Mr Davis examined Mr Blackman’s diaries and used Google Maps to establish the actual distances. In 165 out of 169, the claim was greater than that given by the mapping tool.