LARGE firms should sign up to a "tough code of conduct" to prevent them exploiting workers on zero-hours contracts, Ukip leader Nigel Farage has said.

He claimed cheap labour "flooding in from abroad" had left big employers in an increasingly powerful position to dictate terms for workers.

But Mr Farage acknowledged that the flexibility of zero-hours contracts, which do not guarantee regular work, suited some firms and employees and said he did not believe in banning the arrangements.

It is the latest sign of Mr Farage's efforts to target working-class voters and woo support away from Labour in the run-up to next month's European elections.

Ed Miliband has promised Labour will regulate zero-hours contracts if he becomes prime minister and a Government review of the issue is expected to report in July.

In a newspaper column Mr Farage said: "With so much cheap labour flooding in from abroad, giant corporations are in an increasingly powerful position to dictate terms and conditions for workers."

He added: "Unlimited immigration from eastern Europe and elsewhere has left many British working people pretty much defenceless against constant downgrades in their pay and employment conditions."

Mr Farage said that while having a zero-hours contract as an option was appropriate sometimes for some workers "having it as the only available form of work is quite another".

He added that firms must "show more responsibility towards those on the shop floor" with regards to conditions.

Mr Farage was praised as "charismatic" by the leader of France's far-right National Front, who said her "arms will be open" to Ukip if it wants to join together to fight the European Union.

Ukip told the BBC it is not interested in any deal with Marine Le Pen or her party, adding this is particularly because of "prejudice and anti-Semitism" in the National Front.