LIVERPOOL, England (Reuter) - The 150th Grand National, the most popular horse race in Britain's sporting calendar, will be run on Monday after a suspected IRA bomb scare prevented the original race from starting, police said on Sunday. The announcement came one day after telephoned bomb warnings forced the abandonment of the race -- which draws millions of bets -- and the evacuation of tens of thousands of people. On Sunday, police continued to scour the thousands of cars still stranded at the race course as disappointed race-goers milled around. Merseyside Assistant Chief Constable Paul Stephenson said no devices had been found yet. Prime Minister John Major said he had "no doubt" the Irish Republican Army (IRA), fighting to end British rule in Northern Ireland, was to blame for the spectacular bomb scare and added that such disruptions would only hinder the peace process. He said such attacks, following a spate of similar scares at major road and rail points, would only hurt efforts by the IRA's political allies Sinn Fein to get back into the peace talks. In Liverpool more than 2,000 people were forced to spend Saturday night sleeping on floors next to strangers, in hostels and leisure centres -- wherever they could find an empty corner out of the blustery weather. One couple slept in a hotel sauna, another racegoer in the stable lads' hostel on the course. Princess Anne, horse-loving daughter of Queen Elizabeth, and Oscar-winning actor Gregory Peck, were among the punters who fell victim to one of the biggest evacuations in sporting history. Twenty-four hours after the scare, some 40,000 people were still locked out of their vehicles as security checks continued. Increased security measures were expected close by at Anfield soccer ground, where Liverpool were to play Coventry City on Sunday in a Premier League match, and at Wembley stadium in north London for the League Cup soccer final. At Aintree, race-goers hoped to reclaim their cars and head home but the process promised to be long as police and technical units searched every one of the estimated 7,000 vehicles. Police carried out three controlled explosions on suspicious objects after the coded bomb warnings but all proved harmless. Major warned Britain that the lack of actual bombs or injuries should not be allowed to breed complacency. Britons have grown accustomed to security alerts and bomb scares, and the chief concern of many race-goers was their bets. An estimated $120 million is bet on the Grand National and bookmakers said bets would stand for Monday's 1600 GMT re-run.