After 20 years, numerous lost deposits, criticism and derision, the UK Independence Party (Ukip) is “changing the face of British politics”.

That’s according to party leader Nigel Farage, who promised party delegates the eurosceptics would sweep the board at next year’s European elections then win seats in parliament for the first time in 2015.

A bold prediction, but the party is riding on a wave of self-confidence after winning more than 200 seats in this year’s council elections.

Well if Ukip’s leaders are destined to become a serious force in British politics, they had better get used to the FactCheck treatment. Let’s start with Nigel Farage’s big moment at the party conference in London.

The leader of the UK Independence Party, Nigel Farage, makes his keynote speech at the party's annual conference in central London

factFiction3“We now have 30,000 members and we’re rising fast, and by the time of the next general election we will have the third highest membership of any party in this country, and we’re going up at a time when all the rest are going down.”

These are latest figures on party membership from the Electoral Commission.

PartyMembers2009_NEW

Unfortunately the official figures only take us to the end of 2012 and there have been dramatic developments since then.

Ukip said in July that its membership had passed 30,000. We asked the Liberal Democrats about their latest total and were told we couldn’t have an exact number.

Rather coyly, the Lib Dems told us their membership was hovering somewhere “between 40,000 and 50,000”, an optimistic estimate which would suggest that the speedy decline in Lib Dem membership since 2010 has recently stabilised or reversed itself.

If Ukip’s numbers are correct (and we’ve no reason to disbelieve them), the eurosceptics attracted something like 8,500 new members between March and July this year.

With a growth rate like that, it’s fair to say that surpassing the Lib Dem total by 2015 is a distinct possibility, and if Ukip manage it they will probably have the third highest membership in Britain.

The SNP welcomed its 25,000th member in March this year, so the Scottish nationalists look to be behind Ukip, but the SNP is still growing, so it’s not quite true to say that “all the rest are going down”.

The Conservatives revealed this week that membership is currently running at 134,000, down from just over 250,000 when David Cameron became leader in 2005.

The far-right British National Party, who boasted almost as many members as Ukip in 2010, have suffered a collapse in support. Mr Farage said on Friday that his party does not allow former BNP members to join.

“There have been an astounding 28,000 arrests in the Metropolitan Police area of Romanians in the last five years alone…92 per cent of ATM crime in the capital is already being committed by Romanian gangs.”

The first figure is accurate and comes from a Freedom of Information request to the Met Police, who said they made 27,725 arrests of Romanian nationals between 2008 and 2012.

This was very widely misreported as evidence that an astonishingly high percentage of Romanian immigrants are criminals.

But most reports confused arrests with convictions, underestimated the total Romanian population and neglected to mention that one person can be arrested a number of times.

The Romanian ambassador to the UK, Dr Ion Jinga, wrote a detailed comeback, saying that there were 9,540 convictions in England and Wales out of a Romanian population of 100,000 to 120,000 in 2012.

That would be a conviction rate of 7.9 per cent, if every conviction represented a different person. But there will be many cases where one offender gets multiple convictions, bringing the true rate down. Dr Jinga said most of the offences were not serious, with 64 per cent of them theft.

What about 92 per cent of cash machine crime being carried out by Romanians? This figure comes from Detective Chief Inspector Paul Barnard, formerly of the Dedicated Cheque and Plastic Crime Unit.

A spokesman for the unit said the figure was “based on police intelligence”, but the underlying data has not been made public.

Readers who work for the police will probably not be surprised at a particular network of gangs from one country cornering the market in one specialised type of crime.

FactFiction2“More people settled in this country in 2010 than came here for the previous 1,000 years.”

We’re going to assume that he doesn’t mean that the cumulative total of immigration over the whole of the last millennium was greater than in 2010.

Presumably he means that more foreigners arrived in 2010 than in any previous year.

This isn’t quite right. Net migration did hit a record high of 252,00 people in 2010. But that’s immigration minus emigration, and it only spiked in that year because fewer people left this country than usual.

Actual immigration for the whole of 2010 was steady at 591,000. The inflow was slightly higher in 2006 at 596,000.

Clearly, Mr Farage is making the point that mass immigration in recent years (about half a million a year) is of a different scale than anything Britain has experienced before, and that may well be correct, although the further back in history you go, the less likely there are to be historical records.

Census records suggest that the African-Caribbean and South Asian population of the UK went up by some 300,000 between 1951 and 1961, much of which is presumably attributable to immigration, but there are no reliable migration statistics that are comparable to modern datasets.

Figures from the International Passenger Survey, based on interviews with people who arrive at UK ports, begin in 1964. They suggest annual immigration of around 200,000 people a year until the mid-1980s. For most of this time more people left the country than came in.

20_1964_migration_fc

So far so good for Mr Farage.

Of course, there have been other major waves of immigration throughout British history: Russian Jews in the late 19th century; Irish people earlier that century; French protestants in the 16th and 17th centuries.

But it’s difficult to come up with sensible estimates about the numbers of people involved. Many historians estimate that around 50,000 Huguenots came to Britain in the late 1600s, a significant number when the British population was around 5 million.

Mr Farage is not alone in his historical assessment. Academics from the Migration Research Unit at University College London have said: “Opening up the labour market to citizens of the new member states of the European Union from May 2004 initiated what is almost certainly the largest single wave of in-migration… that the British Isles have ever experienced.”

By Patrick Worrall