Security is being stepped up at hundreds of railway stations, airports, ports and power stations amid fears that suicide bombers could strike at "soft targets".
Advice on guarding against terrorism will also be sent to all the country's schools, hospitals and places of worship, as well as to thousands of cinemas, theatres, restaurants, hotels, sports stadiums and shopping centres.
Gordon Brown announced the moves in a wide-ranging package of measures to boost protection against terrorist attack and to prevent young people from being radicalised by violent extremists.
The moves follow the failed suicide attacks in June on a London nightclub and Glasgow airport and the disclosure of a plot to bomb the Bluewater shopping centre in Kent.
The security clampdown could lead to airport-style security checks on travellers and their baggage at 250 of the country's busiest 2,500 railway stations. Crash barriers will be installed around stations and ports, extra controls introduced on unauthorised vehicles, and buildings protected against the effect of bomb blasts. Security will also be increased around more than 100 "sensitive installations", such as nuclear power stations.
The measures – recommended in a report by the Security minister, Lord West of Spithead, on protecting crowded places – could mean extra delays for passengers.
Mr Brown told MPs that no "major failures" in security had been identified by Lord West. But he added: "Just as we are constantly vigilant to the ways in which we can tighten our security, so too we must ensure the travelling public are able to go about their business in the normal way."
The Prime Minister also announced that strict restrictions, imposed on some air travel last year, would be eased. Passengers will be allowed to take more than one item of hand luggage from next month.
Advice on improving security will be distributed to all major entertainment and sporting venues. Private companies will have responsibility for protecting the public in busy venues and for picking up the bill for security work. Up to 160 counter-terrorist specialists will be appointed to give advice to staff on spotting suspicious behaviour.
Plans to launch a new UK border agency next year, bringing together Customs and immigration officers with extra powers, were confirmed. For the moment, the agency will not include the police, although the Government said a full merger, as advocated by the Conservatives, was possible.
Ministers also signed a £650m contract yesterday with Raytheon Systems, the arms manufacturer, to introduce electronic checks on everyone entering and leaving Britain. The checks will be phased in between 2009 and 2014.
Mr Brown said the size of the security service will increase from 3,300 personnel now to more than 4,000. An extra £240m will be set aside to boost counter-terrorism work.
He also told MPs it was important to win the battle of hearts and minds, announcing a series of measures to "root out terrorist extremism" in mosques, schools, universities, youth clubs and prisons and on the internet. He admitted this it could take a generation to achieve.
Mr Brown promised that terrorist prosecutions will be made more efficient with the development of 14 specially protected courtrooms and the appointment of a single senior judge to manage all terrorism cases and of a single lead prosecutor responsible for cases of inciting violent extremism.Reuse content