"I'm not that interested in Nigel Farage," Ed Miliband said recently when asked about the Ukip leader. But to paraphrase Trotsky on the dialectic, Farage is certainly interested in him - and in his voters. The Ukip leader has made it clear that he believes there are few Conservative voters left for his party to win over and that his focus is on attracting supporters from Labour. With Ukip taking the lead in the most recent European election polls, he appears to be having some success.

In response, ahead of its campaign launch tomorrow, Labour is stepping up its Ukip attack. In an article in today's Daily Mirror, Miliband denounces the party's policies as "more Thatcherite than Lady Thatcher herself."

Now we have Ukip and Nigel Farage pretending that they are the real champions of Britain’s hardworking people. This is from a politician who likes to boast that he is the only one 'keeping the flame of Thatcherism alive'. And the truth is that Ukip's policies towards working people are more Thatcherite than Lady Thatcher herself. His party promises higher taxes for working families and huge giveaways for the rich. He wants bankers’ bonuses to be bigger, while risking 3.5 million jobs by pulling out of the EU and scrapping basic rights at work, like maternity or sick pay. One of his MEPs has even claimed 'the very existence of the NHS stifles competition' and his party wants to impose charges for visiting a GP. I have a clear message for Ukip and Mr Farage: you cannot claim to be a party for working people when you would destroy jobs, our health service, and basic rights.

Rather than attacking the party over its stance on immigration and Europe (precisely the policies that attract working class Labour voters), Miliband has wisely chosen to fight on the territory of the economy and public services. This has the dual benefit of dissuading left-wing voters from supporting Ukip and of reminding right-wing Tories why they have jumped ship. Labour strategists regard the party's recent victory in the Wythenshawe by-election, where it won a comfortable majority of 8,960 (37.4 per cent) over Ukip, as a template for how to fight Farage. The party ran an effective get-out-the-vote operation and attacked Ukip over its support for tax cuts for the rich and GP charges.

Most of Ukip's supporters, as I've noted before, favour a large state and higher public spending. Polling by YouGov shows that 78 per cent support the nationalisation of the energy companies and 73 per cent back the renationalisation of the railways. Rather than a "code of conduct" for employers, 57 per cent simply want zero-hour contracts to be banned. Rather than a flat tax, the same number support the reintroduction of the 50p rate.

But there are signs that Farage is shifting leftwards on the economy in a sign to retain their support. He has recently called for tougher regulation of zero-hour contracts and for the abolition of the bedroom tax. Farage has also abandoned Ukip's previous policy of a flat tax of 31 per cent, arguing that higher earners should pay at least 40 per cent.

Given Ukip's success in attracting working class supporters, it makes no sense for the party to alienate them by adopting a programme of turbo-Thatcherism. In this era of insecurity, there is a large market for a party that combines hostility towards the EU and immigration with a critical stance towards big business. As Farage and his allies know, it is this approach that has enabled the Front National to achieve such success in France. The challenge for him will be to continue this reorientation without entirely alienating his party's libertarian wing.

P.S. With both Miliband and Farage appearing on The Andrew Marr Show this Sunday, we can look forward to the first encounter between the pair on the usual sofa slot at the end.