The hour before lunch last Friday was a bad one for two former Labour MPs. First, the High Court ruled that an election court had acted lawfully when it found Phil Woolas guilty of an ‘illegal practice’. There was just time to hear Woolas announce that he would not be seeking to appeal before taking a quick bus ride along Fleet Street to the Old Bailey, where David Chaytor pleaded guilty to making three dishonest claims for parliamentary expenses. That amounted to two political careers over in half an hour but, I hope, a more honest approach to politics in the future.

Chaytor is to be sentenced on 7 January. Will he go to prison? The maximum penalty for false accounting is seven years. But current guidelines for fraudulent claims of between £5,000 and £20,000 advise the court to take 12 weeks’ custody as its starting point.

In Chaytor’s case, the starting point is likely to be higher. The former MP admitted falsely claiming £20,300 for rent and IT services, although he says the IT claim – £1,950 – was never paid.

Any defendant who pleads guilty at the first reasonable opportunity can expect to have his sentence reduced by a third. Chaytor argues that he did just that; it was only last week that the Supreme Court gave reasons for deciding that he could not claim parliamentary privilege. The judgment was very much as expected, upholding earlier rulings by the Court of Appeal and the trial judge, Mr Justice Saunders. Even so – and although the trial had been due to start on Monday – I am sure the judge will give Chaytor full credit for his guilty plea.

The defendant’s previous good character must count for something in mitigation. So will the judge’s duty not to send Chaytor to prison unless his offences are too serious to justify a community sentence. Even if Saunders does conclude that a short custodial sentence is justified, he could suspend it. All in all, I would not expect Chaytor to receive an immediate custodial sentence.

Nor do I think that the judge should be too worried at the prospect of the public outcry that might follow if the convicted MP was thought to have ‘walked free’. Plenty of MPs claimed expenses that were unjustified. I don’t think the public quite understands why some of them are facing criminal charges while others are running the country.

Woolas’s misconduct was of a very different kind. He was found by an election court to have made three false statements of fact in relation to the personal character or conduct of his Liberal Democrat opponent that he did not believe to be true and had no reasonable grounds for believing were true. The statements were made in leaflets for which Woolas accepted responsibility and which were distributed during the general election to voters at Oldham East and Saddleworth.

Woolas won the seat by a majority of 103 votes over Elwyn Watkins, his Liberal Democrat opponent. Under laws that have remained largely unchanged since 1895, a finding that the elected MP is guilty of an illegal practice renders the election void. He must vacate his seat and cannot hold elective office for three years.

There is no right of appeal, as such, against the finding of an election court. So Woolas sought to apply for judicial review, the process by which the High Court can put right errors of law made by inferior bodies. But an election court dealing with a parliamentary election is made up of judges from the High Court itself. Is their decision open to judicial review?

That was a question the courts had never been asked before. But I was not surprised that three judges headed by Lord Justice Thomas decided last week that they had the necessary jurisdiction to review the decision of a parliamentary election court. Even though it consisted of High Court judges, they decided that an election court was a tribunal of inferior or limited jurisdiction. That meant the High Court could correct any errors of law it had made.

It was a partial victory for Woolas. He was given permission to seek judicial review, even though he should have brought his challenge using other procedures while the election court was still sitting.

The next question for the High Court was whether the election court had used the correct legal test in deciding that the statements Watkins had complained about related to his ‘personal character or conduct’. This issue was last considered 99 years ago by a court sitting in what is now Ireland.

On this, Woolas also had some success. The High Court decided that a statement must be either personal or political; it could not be both. One of the false statements made by Woolas – that Watkins had reneged on a promise to live in the constituency – had been wrongly categorised by the election court as personal. False statements about a candidate’s political position or character could not amount to illegal practices.

But the election court had been right to say that two other false statements about Watkins had gone beyond political allegations and amounted to statements about his personal character. These were the entirely untrue allegations that the Liberal Democrat had wooed the support of Muslims who advocated extreme violence and that he had refused to condemn threats of violence by extremists.

These lies amounted to a ‘serious personal attack’ on Watkins and entitled him to have the vote set aside. But the Liberal Democrat may find winning the forthcoming by-election rather more of a challenge.