A Liberal Democrat parliamentary candidate was warned by one of his leading campaigners to stay away from a visit from party leader and Deputy Prime Minister Nick Clegg to avoid “being associated with the leadership right now”.

Maajid Nawaz, Lib Dem candidate for Hampstead and Kilburn, was advised by friend and Lib Dem campaigner James Newsome not to join Mr Clegg on a visit to the Tavistock Centre, in Belsize Lane, Swiss Cottage, on Friday last week.

In an e-mail to Mr Nawaz, which was mistakenly sent to the Ham&High, Mr Newsome said being associated with Mr Clegg “blunts the progress we are making”.

He wrote: “M, I am on same page as I was when this visit first came up. We don’t need to be there.

“In fact you being associated with the leadership right now blunts the progress we are making with these young volunteers and the crossover pledge momentum we are getting.

“You are a top 500 Briton in Debretts Guv, let’s let Nick do his own thing, which is good in itself, right? J.”

Mr Clegg has been dogged by criticism since his party entered into coalition with the Tories in 2010 and caused outrage after failing to deliver on a pledge to oppose a rise in university tuition fees.

His party currently hover at around six per cent of the vote nationally, according to most polls.

Last month, Mr Nawaz, who did meet with Mr Clegg during his visit to the specialist mental health centre, was named in the prestigious Debrett’s 500, a list of Britain’s top 500 most influential people, for his work as co-founder of counterterrorism think-tank Quilliam.

City banker Mr Newsome, who stood as a Lib Dem candidate for Hampstead Town in May’s local elections, said the “young volunteers” mentioned in his e-mail referred to traditional Conservative voters who have pledged to vote Lib Dem because of Mr Nawaz.

Stockbroker Freddie Bellhouse, 30, of Victoria Road, Queen’s Park, said he was politically on the “left-hand side of the Tory party” but has been campaigning for the Lib Dems because of Mr Nawaz.

“If it wasn’t for Maajid, I wouldn’t be voting Lib Dem and I know people in my friendship group who are exactly the same,” he said.

“Maajid is clearly a classic liberal and is pro-free markets. He also has a big part to play in parliament in terms of extremism.”

During his visit last week, Mr Clegg pledged to spend £500million a year on better mental health care in the next parliament.

Mr Nawaz is a passionate supporter of mental health charities Mind and CALMZone.

Asked for his views on the damaged popularity of his party, which lost 12 of its 13 seats on Camden Council in May, Mr Clegg told the Ham&High: “Clearly us going into coalition – putting the country before the party – is controversial and unpopular with some people.

“But just imagine if we hadn’t created a stable government. Our deficit was pretty well the same as Greece’s back in May 2010 and look at the difference between the two countries now.”

A Lib Dem spokesman said: “Maajid joined Nick on his visit to the Tavistock, he has been at Nick’s side in the past and will be in the future as he fights to win Hampstead and Kilburn.”