Tom Wise, a bon viveur who once boasted of his “cushy job” doing frankly very little as an MEP for the UK Independence party (UKIP), became, last Thursday, the first British politician to be convicted of expenses fraud for more than 10 years.

It was a victory for justice, and a victory for me, too. Four years ago I wrote an exposé accusing Wise of claiming £36,000 a year in expenses to pay for a researcher, Lindsay Jenkins, while passing on to her only a fraction of that sum. The story prompted a European Union inquiry, which was eventually referred to the British police, as was acknowledged in court last week.

In the intervening years I continued digging, uncovering bank statements and contracts that proved Wise blew thousands on a car and fine wine, as well as paying his credit card bills. The resultant stories prompted UKIP to remove the whip from Wise but not to expel him; he continued to sit in Brussels until stepping down at the Euro elections in June.

The case will have had ominous overtones for several MPs and peers currently under investigation by the police over their own expenses, in the same week that Sir Christopher Kelly announced his crackdown on the widespread profligacy of our parliamentarians.

UKIP’s leaders were falling over themselves last week to condemn Wise. The party’s chairman, Paul Nuttall, said: “We believe as a party it is vital as a matter of public trust that justice is done.” But UKIP’s commitment to seeing “justice done” leaves a lot to be desired.

After my first article, the party rallied round Wise, insisting he had done nothing fundamentally wrong. Nigel Farage, a UKIP MEP who went on to become the party’s leader, even breezily told me that Wise had committed a simple, silly error by making himself a “paying agent” for his own staff, something that was against the EU rules to prevent fraud.

Back then, party bigwigs, including Farage and the leader at the time, Roger Knapman, said they could “not state strongly enough that at no time has Mr Wise attempted to seek personal gain”. Furthermore, Knapman said, the party’s own inquiries had satisfied him that Wise’s actions had been “honest and honourable throughout”.

However, it turned out the party had been aware, even before my original exposé, that Wise had a bank account with tens of thousands of pounds in “surplus” funds sloshing around, thanks to an underspend on his expenses. And several thousand pounds that Farage had promised Jenkins as part-funding for a Eurosceptic book she was writing had even somehow found its way to her out of Wise’s account.

UKIP must have known that MEPs are not allowed to come into contact with taxpayers’ money that is designated as salaries for their assistants. EU rules state that assistants nominated by an MEP must be paid directly from Brussels or else via a third-party agent. The fact that one of its MEPs had in his possession a “surplus” on his assistant’s allowance should have sounded warning bells. Yet it was an alarm that UKIP chose to ignore.

Six months after my first article, the party was still confident that the whole matter had gone away. The EU payments office had written that it would take no further action — it later emerged that the office had passed the matter to official investigators — since Wise had rushed to pay back £25,000 after the exposé. UKIP pronounced that Wise was “cleared” and threatened to sue me.

UKIP’s internal inquiry had concluded there was no case to answer: the party claimed it had looked at the paperwork. It couldn’t have looked very hard. When I managed to obtain copies of the relevant documents, Wise’s was the most blatant, open-and-shut case of fraud I have ever come across. On the contract he submitted, Wise had simply put his own bank account number next to Jenkins’s name, so that the EU payments office would think it was paying her directly.

Wise had told Jenkins he would pay her £500 a month, plus extra for any ad hoc work done. She later told the police that she had signed the forms he sent her even though they were blank. He had then filled in the £36,000 annual rate that he claimed in her name and submitted it. Much of it he ended up spending on himself.

Jenkins, 62, was initially charged, but when Wise admitted his guilt last week she was acquitted of all charges. In court, the bearded and bespectacled Wise cut a pathetic figure for a man once elected in the name of a party committed to ending the EU “gravy train”, though his arrogance remained intact.

It was a quality that had first struck me four years ago when he had attempted to bluster his way through my questions about his employment of Jenkins. Later, when he had been supposedly “exonerated” by the EU payments office, he had pompously said that my “attack on his character” had not deterred him from his important work. Wise even took legal advice on how to sue a political commentator who wrote blogs on the story, paying for it — although he did not proceed — with taxpayers’ money from the same fund he was accused of abusing.

Arrogance is a quality that is not in short supply within UKIP; nor is an ability to dissemble and prevaricate. As Wise awaits a possible jail term at his sentencing this week, who knows which politician and which party will enter the dock next.

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