Postal regulation in Britain is set to enter a "new phase" after it was announced that current watchdog Graham Corbett is to leave his post.

In a written statement to the Commons, the trade and industry secretary revealed that the government will not be renewing Corbett's contract.

The decision to terminate his tenure as regulator after only three years reflects ministers' anger with the confrontational approach he brought to his office.

Corbett has clashed repeatedly with the Post Office over issues such as stamp pricing and the speed at which the postal market will be liberalised.

The government is under pressure from MPs to ensure that the struggling firm is not pushed over the edge by Corbett's hardline attitude towards regulation.

Critics have argued that Corbett was unable to tread the tightrope between ensuring consumer rights and the business viability of the different postal operators.

A spokesman for Postwatch, the consumer's watchdog, defended Corbett's record, noting that "regulators don't seek and rarely achieve popularity, and Graham had a very difficult job".

Meanwhile a Post Office spokesman welcomed the change.

"We hope this marks a new phase in how the postal service is regulated and are pleased that the government seems to have taken on board our criticisms about the way that Postcomm has operated," said Peter Skyte.

Corbett claims that he had already decided to step down at the end of his initial contract, having successfully laid the foundations for reform of the postal network.

Martin O'Neill, chairman of the trade and industry select committee, said the introduction of market forces was likely to continue in postal services.

"Graham Corbett has laid out the way in which postal services will be opened up to competition and once this die has been cast it is hard to see how any replacement is going to change things radically," he said.