Andy Burnham must take his chance to bury Nigel Farage

Nigel Farage, the leader of Reform UK, has tried to brush aside the allegation that two of his aides conspired to get around the law against foreign donations, calling the covert filming by Channel 4 reporters “entrapment”.

Mr Farage has spoken dismissively of “a couple of contractors” making an “error of judgement”, which simply will not wash. James Orr and Dan Jukes have been suspended, but are “not coming back” according to Lee Anderson, the chair of Reform. Both were close advisers to the Reform leader. Mr Jukes in particular had been in effect Mr Farage’s press secretary and principal adviser for more than a decade, one of Mr Farage’s “lifers”.

The extent to which Mr Farage himself knew of any willingness to break the law may be established by a police investigation, but Mr Orr’s comment that Mr Farage “doesn’t know, won’t know” and would “rather not know” does not reflect well on him.

The allegations are a serious embarrassment for Mr Farage and his party, at a time when Reform has been losing support in national opinion polls for many months. That decline reflects Mr Farage’s poor handling of legitimate questions about why he failed to declare a £5m personal gift that he received shortly before the general election. Parliament’s rules require the disclosure of any donation “related to … political activities” received in the year before election to the Commons.

And it reflects a more general feeling that Reform is not ready to be a party of government – and that Mr Farage is not ready to be prime minister. The party’s policies are unconvincing. This week’s claim by Robert Jenrick, Reform’s economic affairs spokesperson, that he would cut public spending by £100bn a year in the first 100 days of a Reform government was not endorsed by any independent economists.

This week, too, Mr Farage was embarrassed by his support for Donald Trump when the American president disparaged Britain’s claim to the Falkland Islands.

What is more, Mr Farage’s decline is mirrored by Kemi Badenoch’s rise. She has shown confidence and fiscal responsibility as she has challenged Mr Farage for leadership of the right.

But Mr Farage’s setbacks are also an opportunity for Andy Burnham. He proved in the Makerfield by-election, returning to the Commons, that he can take on Reform on its own turf. He should now do that at the national level.

The prime minister should use this moment, when floating voters are being repelled by Mr Farage’s sleaze and incompetence, to make his pitch on the issues of concern to them. They want firm and fair control of immigration, they want a government that is tough on crime and tough on the causes of crime, and they want competence.

Mr Burnham has done some of the right things. He has backed Shabana Mahmood, the home secretary, in her resolute approach to immigration control. He has strained every sinew to minimise the number of the worst criminals who will be released early as a result of the Conservative government’s mismanagement of the prison system.

But he needs to move further in that direction, and not listen to the siren voices to his left, urging him to focus instead on winning back voters who have abandoned Labour for the Green Party.

So far, Mr Burnham has shown that he can win back voters from the left and centre simultaneously. Mr Farage’s decline has happened at the same time as some of the air has gone out of Zack Polanski’s Green balloon.

Mr Burnham should keep his eye on the prize. Many of Mr Farage’s erstwhile supporters are not ideological right-wingers: they are disillusioned with politics and politicians. Mr Burnham has made a good start in offering hope to the sorts of places where Reform was strong, including working-class communities in the north of England. He should make sure that Mr Farage does not recover.