Disillusionment with Tony Blair and Labour is so entrenched that many voters will assume the government is guilty in the cash for honours affair even if no charge is ever brought, opinion pollsters said on Friday.

Experts also said the longer the police inquiry into the allegations drags on, the greater the risk that voters’ loss of trust in Mr Blair contaminates the Labour brand as a whole, potentially damaging the electoral chances of Gordon Brown, his expected successor.