Home Secretary Theresa May was set to update MPs on the probe into the tuition fee protests that rocked central London last week.
The statement to the Commons comes amid speculation that police could toughen their tactics following criticism of the way they have handled the recent demonstrations.
Mrs May refused to be drawn on specifics but said Scotland Yard was looking at measures “across the board” – leaving the door open for the use of water cannon.
She also confirmed that the Duchess of Cornwall had come into contact with protesters who attacked a Rolls-Royce carrying her and the Prince of Wales through the West End on Thursday.
In future the royal couple may be forced to abandon the historic Phantom VI – which was given to the Queen to mark her silver jubilee in 1977 – because it is too distinctive and not manoeuvrable enough.
Metropolitan Police commissioner Sir Paul Stephenson is said to have offered his resignation in the wake of the security breach, but it was turned down.
Mrs May defended the “robust” police response to the disorder that saw thousands of protesters “kettled”, and insisted thugs who climbed on the Cenotaph war memorial and defaced Winston Churchill’s statue would be punished.
Meanwhile, two more people arrested by police investigating disorder during the tuition fee demonstrations are in custody. Charlie Gilmour, the son of Pink Floyd frontman David, was arrested on Sunday at his home in Sussex. And a 17-year-old who was allegedly in one of a first batch of 14 pictures of people wanted in connection with violence at the protest handed himself in.
Gilmour, 21, was held on suspicion of violent disorder and attempted criminal damage of the Union flag on the Cenotaph on December 9. He was taken to a Sussex police station where he was also arrested on suspicion of theft. He remains in custody.
Separately, the political fallout from the tuition fee row continued, with senior Liberal Democrats pleading for unity after the party’s damaging split on the issue. Deputy leader Simon Hughes admitted there was massive anger among grassroots and MPs over the issue, but urged people to recognise the wider benefits of being in government. And Treasury Chief Secretary Danny Alexander described the coalition as “rock solid” and insisted partnership with the Tories was the “only way out” for the party.