WATCH: Nigel Farage - We can win in the Black Country and Staffordshire

The UKIP leader visited the Express & Star after a tour of marginal seats in the West Midlands that are major targets for Labour and the Conservatives.

And he said he did not regret saying he would quit as leader if he fails to win a seat in Parliament for himself - as opinion polls suggested it was very close in the southern constituency he is fighting.

The UKIP leader also suggested that he might ban former Tories from joining the party, blaming 'problems' with some candidates expressing politically incorrect views on them.

Mr Farage named Dudley North as a seat where UKIP 'fancy our chances'. UKIP also picked up council seats in Walsall, Wolverhampton and Sandwell in the elections last year.

It is held by Labour's Ian Austin by a majority of 649 votes.

The UKIP leader said: "It's a part of the country we have been building steadily over the past couple of years.

"People see politics and parties paying hundreds of thousands of pounds for spin doctors and advisers.

"We have a serious base here and thought for some time that Dudley as an area presented us an opportunity.

"I think we are in with a very realistic chance. When we fought the Labour seat of Heywood and Middleton, the polls had us 20 per cent behind. They were wrong.

"We fancy our chances."

David Cameron has pleaded with former Tory voters to reject UKIP and said: "To keep generating the jobs and the growth our country needs, come back to us, come back home to us."

But Mr Farage said: "The UKIP vote doesn't cut that way anymore. Those who voted for us who were Conservatives in 2010, it's a much lower figure than you imagine.

"The people that re-elected Mark Reckless (the former Tory who defected to UKIP) had not voted Conservative in 2010.

"If just a few more Conservatives had voted UKIP to beat Labour, we would have won in Heywood and Middleton.

"There are seats in which the very opposite is true.

"Getting a good share of the vote is important. For the longer term the commentators will look at where we come second. My suspicion is in the north of England we are emerging as the only real opposition to the Labour party.

Many parts of the Midlands are similar. From Birmingham to Hadrian's Wall, the Labour party need to be worried about UKIP."

The UKIP leader yesterday spoke at Himley Hall where he promised to spend £16 billion extra in the next parliament to meet minimum NATO spending targets.

He rejected criticism about plans to pay for this via cuts to international aid, insisting 'defence of the realm' was the first priority of government.

He also announced plans for a Veterans' Minister and a medal for all service personnel, before last night addressing a public meeting at the Copthorne Hotel in Dudley.

Mr Farage said he wanted to see a change to the voting system to bring in proportional representation so that UKIP had a chance of winning more seats.

"I've felt for years that First Past The Post is bankrupt. With two party politics it worked. It has stopped working. If you are in a safe Labour seat but you take an opposing opinion, what's the point of voting? A lot of the older generation felt it was what they fought for. Younger people think, what's the point?

"I'm an advocate for broader political reform."

But he denied that the party's bubble had burst, despite recent growth in support for the Tories and Labour.

"The normal phrase is the UKIP fox has been shot," he said. "It must be extinct, the number of times I've heard that.

"We had a 34 per cent turnout last year as opposed to what is likely to be a 60 per cent turn out.

"Last year we were at 14.5 per cent. We are now at 14.6 per cent. We are where we were after we won the European elections."

On his own pledge to resign if he fails to win in South Thanet he said: "It's a statement of the obvious. If I fail, I'm a goner. Most party leaders could be gone by the end of the summer. It ups the stakes. I believe I'm going to win."

But he said he did not think the party should just concentrate on 35 seats where it might have a better chance of winning.

"If we did that we would be saying to voters in 600 seats 'we are not interested in you'," he said. "Those voters deserve the chance to vote for us.

"We ought to bar people who had formerly been elected Conservatives from coming to us.

"They have given us almost every problem we've had. We've had one serious incident over the last few months. That was Janice Atkinson."

Miss Atkinson was expelled for 'bringing the party into disrepute' over false expenses claims.

"That was bad news," Mr Farage said.

"When some UKIP town councillor says something somewhere on a website at 10.30pm at night it becomes a national story. We see other councillors from other parties imprisoned and we get two lines.

"There's a disproportionate reporting of that."

He said he did not believe he could work with a Labour government run by Ed Miliband adding: "Politics is becoming fragmented. Mr Miliband turned his back on the British people having a say on the European question. No, how could I? Unless there's a change of heart. Labour are pro-EU, there's no chance."