A range of tough new security measures are being planned to protect parliament from terrorist attack, according to a leaked report.

Among the measures proposed in the confidential study, leaked to the Sunday Times, are road closures and electric fencing around the perimeter of the Palace of Westminster.

The report comes as MPs and peers continue to debate parliament's reaction to recent security lapses.

The Fathers 4 Justice purple "bomb" attack on the prime minister and the invasion of the Commons chamber by hunt supporters were both major embarrassments for the parliamentary authorities.

But while Commons leader Peter Hain has urged a security shake-up, other MPs have expressed concern that radical reforms could make politicians more remote from the public.

The latest report appears to indicate that access to parliament for protestors and members of the public will be maintained.

But a range of measures are set to be implemented to address the key fear that a terrorist suicide mission involving a truck or boat bomb could devastate the historic parliamentary buildings, possibly bringing down Big Ben.

The Sunday Times reported that a joint Commons and Lords security committee had already endorsed the report's findings.

Measures being proposed include the installation of electric fencing around parliament's perimeter, road closures in Parliament Square, rising bollards to protect against truck bombs, and a floating boom to prevent attacks from the Thames.

There will also be greater use of CCTV cameras, tougher rules on displaying security passes, and a permanent bullet-proof screen across the public gallery in the Commons.