Labour sought to give its campaign for re-election in Southampton a boost with a visit from PM Gordon Brown.

But on one of the key local dividing lines in the election the Prime Minister again washed his hands of calls for a vote on adding fluoride to the tap water of 200,000 residents in and around the city.

As he arrived at Solent University’s Sir James Matthews Building, he was cheered by supporters, although a few boos could also be heard.

Mr Brown was greeted by Labour candidates for Southampton Test and Itchen, Alan Whitehead and John Denham, and Portsmouth North candidate Sarah McCarthy-Fry.

For an hour he fielded a wide range of unscripted questions from voters in one of his toughest question and answer sessions so far on the campaign.

He told the Daily Echo that he put job security and the future of public services as the top priorities for Southampton and said that they both depended on rebuilding a strong economy.

But when asked why residents did not deserve a referendum on the controversial decision by health chiefs to add fluoride to parts of the city’s water, Mr Brown again distanced himself from the issue.

He said: “That’s a decision for the local health authority.

Of course we want people to be able to make local decisions and national decisions and that’s why I’ve proposed a referendum on the constitution but it’s not for me to dictate how people in Southampton make their local decisions.”

Daily Echo: Brown washes hands of calls for fluoride vote

Mr Brown seized the opportunity to reel off Labour’s successes and future plans behind a wheatfield backdrop declaring "a future fairer for all”.

He praised Southampton as a “great city” and said, thanks to a £30m Government grant to the University of Southampton, it would be developing the “next generation of the web” – crucial to future jobs and prosperity.

He opened his pitch by telling one undecided voter and small businessman – Southampton public relations man Lee Peck – that Labour’s plans for “securing the recovery” and expanding the “digital economy” were reasons to vote for them.

Mr Brown went on to take questions on tuition fees, state pensions, antisocial behaviour, the approval of new drugs, Europe and immigration, schools and why Britain was fighting in Afghanistan.

He was also criticised about the lack of support for armed forces families. A woman, who said she was herself a forces dependent, told him the housing was “appalling”.

“We have lost dental care, we have lost medical care.We have to move every two years or so and we don’t get any support in schooling for our children,” she said.

Daily Echo: General Election news from the Southern Daily Echo

The Prime Minister said that members of the armed forces had “a right to expect their families and they themselves will get access to the services that they need in the British public sector”.

Mr Brown also promised to have a private chat with one questioner who broke down in tears when he explained the problems of finding a job because of his dyslexia.

The Prime Minister said he would ensure that the man received help, adding: “I know the difficulty you have got. You are a good man. We will get you help.”

But when the issue of local Tory proposals to replace permanent council staff with volunteers at Southampton libraries came up, he deferred to Mr Whiteahead to criticise the plans.

However, in principle Mr Brown said that he wanted to see a “partnership between the professional and the voluntary sector”.

Mr Brown reminded the audience that he was “not a PR person” nor “someone who knows about style” and said that he wanted people to come out and vote Labour based on its policies – about jobs, the economy and the heath service.

His visit to Southampton came just hours after Tory leader David Cameron had toured the rival University of Southampton, and Mr Brown admitted that he was not taking any votes for granted.

Meanwhile, Lib Dem leader Nick Clegg yesterday indicated that he would be prepared to support a Labour Party which had slumped to third in the vote share, but would not let Mr Brown retain the keys to No 10.

With opinion polls pointing to a hung Parliament, Mr Clegg said that it would be “inexplicable” for Mr Brown to remain as Prime Minister if his party had finished with fewer votes than the Tories or Lib Dems, even if Labour had the most seats.