The UK Independence party has been caught "telling fibs" after it moved to shore up its vote among struggling small business owners by claiming that the EU is planning to restrict the work of car repair garages just as the government succeeded in rejecting such a proposal in Brussels.

As Nigel Farage pledged to change the image of his party, by highlighting the large number of black and minority ethnic candidates standing in the local elections, the government said that Ukip's claims were untrue after ministers "stood up for Britain" in the EU.

Stephen Hammond, the transport minister, spoke out after Ukip sent out a leaflet inviting garages to tell the EU "where to go" because Brussels wants to strip them of the right to conduct MOT tests and to repair vehicles.

Warning of another EU initiative telling people how to run their lives, the leaflet says: "This one strikes at the very heart of your livelihood. Your working life will be changed forever. And your income. Join Ukip and stand up to the EU bullies … Together, we can fight this new threat to our way of life."

But Hammond said that he succeeded in beating off a proposal in a draft package of EU roadworthiness directives that would have separated testing from repair and maintenance – dealing a blow to garage repair centres which carry out both functions.

The minister told the Guardian: "I understand Ukip are saying that our MOT and much of the UK testing regime is under threat from Europe. Had I not stood up for Britain, this might have been true. However, after our actions this is simply untrue and it is yet another example of Ukip telling fibs rather the truth."

The government fightback against Ukip came as Farage said that he would show his party reflects modern Britain by unveiling the large number of black and minority ethnic (BME) who will stand for the party in the local elections.

Farage insisted his party was not racist after the Sunday Times reported that a Ukip candidate in Liverpool appeared to call on social media for the burning of the Qur'an. Paul Forrest also described the Catholic church as the "anti-Christ" and said that gay men are 10 times more likely to be child abusers than straight men. Forrest, who is standing in the Clubmoor ward of Liverpool, appeared to have removed his remarks about Islam from his Facebook page.

The Ukip candidate had written: "The end of Islam is coming, and a great destruction it will be. All the trappings of their false religion, gone. All its followers who never abandon it and turn to Christ, gone. We don't have to burn the Koran – God's going to do that for us."

Farage told the Andrew Marr Show on BBC1 that his party has made mistakes in the selection of candidate. But he added: "These people are not representative of Ukip at all – not only am I adamant that we are a non-racist party, this week we are going to fight back against it. You will see our election address for the local elections this year and you will see a lot of black ethnic minority candidates who are proudly standing for Ukip. I am going to approach this differently in future."

But Farage also claimed that the enlargement of the EU to include former Warsaw Pact countries has created a "gateway for organised crime". Expanding on his answer in a Guardian interview last month, when he spoke of how discomfiting it would be to live next door to Romanians, Farage told Marr: "We have opened up the doors to countries that have not recovered from communism and I'm afraid it has become a gateway for organised crime. Everybody knows that. No one dares say it."

The remarks appeared to be aimed at Romania and Bulgaria, two former Warsaw Pact countries that joined the EU in 2007. A further eight former Warsaw Pact countries, led by Poland, joined the EU in 2004. Farage is concerned about immigration from these, the so-called A8, but his remarks appeared to be aimed at Romania and Bulgaria because they are less developed economically.

The move by Ukip to change its image came as the pressure facing David Cameron over the EU was highlighted by a new poll which showed that more Tory voters would like to leave the EU. A TNS poll for Global Counsel, the company run by Lord Mandelson, found that 47% of Tory voters would like to leave the EU compared with 37% who would like to remain.

A majority (55%) of Labour voters support Britain's EU membership compared with 25% who would like to leave. The poll found that 62% of Liberal Democrat members support EU membership. Just 22% are opposed.

But there was grim news for Clegg in another poll which found that the Lib Dems have slipped into fifth place behind the Greens in the European elections. The YouGov/Sunday Times poll put the Lib Dems on 7%, one point behind the Greens. Ukip was in the lead (29%), one point ahead of Labour on 28%. The Tories were on 22%.