In his first entry to the campaign in the capital, Mr Brown visited a SureStart centre in Croydon and a training centre at Charlton FC. Mr Brown's comeback will be sealed when he unveils a Labour poster tomorrow and attends the launch of a new housing policy alongside Mr Prescott. One aide said Labour's message will be targeted at those who identify with Labour but are not certain to vote. A minister said: "If this group votes Labour we will secure a third large majority. If they do not, the result will be a lottery."