The government has announced that the centuries-old Westminster lobby briefing system is to be radically reformed - prompting claims that the government is attempting to neuter journalists.

The secretive briefing system, through which the media attends a twice-daily question and answer session with Downing Street staff, is to be overhauled to allow non-accredited and foreign journalists to attend.

In future, the 11.00am morning briefing will be addressed by expert civil servants and ministers as well as Tony Blair's official spokesmen.

The announcement was made by the government's information chief, Alastair Campbell, on Thursday.

A spokesman said it was time to be "less buttoned-up, far more open" - claiming the government wanted to create a situation where it was "far less worried" about what the media was set to write.Lobby journalists reacted with anger to the timing of the announcement - attacking the governments failure to consult with senior members of the body before making the announcement.

They also claimed that ministers could be used to divert media questions away from a topical issue, and suggested that the presence of foreign journalists would reduce the ability of the Westminster press corps to grill the Number 10 spokesman.

The Sun's political editor, Trevor Kavanagh, said: "This government doesn't like the media and this will dilute the flow of the questions.

"As always with New Labour it looks good on the face of it, but on closer inspection we will have to look a gift-horse in the mouth."

Downing Street denied the move was an attempt to neuter the Westminster lobby system.

"The change we would like to make now is to make them more open, to allow in any journalist who wants to attend them to do so. We have huge numbers of complaints from foreign journalists about their access," said a spokesman.

Under the new rules, announced amid confusion on Thursday afternoon, briefings involving ministers could be held "on-camera".

Downing Street defended the chaotic nature of the announcement, saying it was simply pre-empting journalists who had found out about its plans.

A spokesman later said that the prime minister was determined to reform the system but agreed to consult further on the exact nature of the reforms.

There will be no change to the 4.00pm lobby briefing at which only accredited members of the press corps are permitted.