Home Office vans: Unite union in 'race hatred' query 2 August 2013 Last updated at 12:20 The Unite union has said it is seeking legal advice about whether the Home Office "incited racial hatred" by sending vans around London encouraging illegal immigrants to "go home." Its leader, Len McCluskey, called the poster-covered vehicles "vans of hate." Nick Clegg has criticised the pilot scheme, but the Home Office has said the message was not racist. Meanwhile, new peer Doreen Lawrence has said police stop-and-check operations focus "mainly on people of colour." The Labour-supporting mother of murdered teenager Stephen Lawrence, told ITV's Daybreak she thought "racial profiling" was involved. The controversy comes after it was revealed that nearly 140 people had been arrested in a wave of raids aimed at tackling people working illegally in the UK. Free advice The Home Office's week-long immigration publicity pilot scheme involved six vans driving around north London, carrying a board asking: "In the UK illegally?" The poster continued: "Go home or face arrest." It supplied a text messaging number for those seeking "free advice, and help with travel documents." The pilot scheme only ran in six London boroughs and lasted for one week, but the political fall out has been much wider. Unite leader Len McCluskey wasn't alone in condemning the vans. Labour branded the scheme "stupid politics from a government not getting the basics right on immigration." The coalition is split on the issue. Nick Clegg criticised the scheme and was clear that no Liberal Democrat had given it their approval. But Number 10 defended the pilot, which it insisted was working. UKIP leader Nigel Farage, in favour of a tougher stance on immigration, described the message on the vans as "nasty and unpleasant." He said it was clearly aimed at encouraging people not to vote UKIP. The Home Office insists the "go home" message is aimed directly at illegal immigrants. But perhaps the wider message it wants to convey is that this government is serious about tackling illegal immigration, which is likely to be a key battleground in the run-up to the next election. The Metropolitan Police told the BBC it had received a complaint from a person in the London borough of Hounslow. A spokesman added the complainant had been spoken to and advised that the matter had been "recorded as not a crime." Speaking on Wednesday, the deputy prime minister said he was "very surprised" to see vans "driving aimlessly around north London" telling illegal immigrants to go home, and that they were not a "very clever way" of tackling the issue. Mr Clegg told BBC Radio 5 live that no Liberal Democrats - including Home Office minister Jeremy Browne - had known about the pilot scheme in advance. Downing Street had said the vans had been approved by the "Home Office team." No 10 also said on Monday that the pilot scheme using the vans had worked, although the Home Office said it was too soon to make a final assessment as a poster and leaflet campaign was continuing. Separately, Mrs Lawrence, confirmed this week as a Labour peer, spoke out against a scheme where spot checks have been carried out near railway stations as part of a crackdown on illegal immigration. She said: "Why would you focus mainly on people of colour? I'm sure there's illegal immigrants from all countries, but why would you focus that on people of colour, and I think racial profiling is coming into it. Some 139 people were arrested at locations including London, Durham, Manchester, Wales and Somerset. A Home Office spokesman said: "We make no apology for enforcing our immigration laws and our officers carry out hundreds of operations like this every year around London. Where we find people who are in the UK illegally, we will seek to remove them.