But the smallest red and yellow 'Vote Labour' poster somehow managed to gain entry among the usual clientele of suits and mobile telephones.
Delicately waved from a balcony, the offending three inches by nine inches was in danger of providing an interesting background shot for the television cameras as they waited for the Prime Minister's impromptu doorstep press conference.
However, the confrontation was not to be. An eagle-eyed Conservative official called the hotel's duty manager. The man had clearly faced bigger problems and trooped upstairs to where delegates on a National Audit Office training course were having their lunch. The poster's owner quickly found her break was over.
Moments later John Major appeared, brimming with confidence. 'I regard the local election campaign as extremely important,' he said, pledging his support to Croydon Conservatives, who face the prospect of electoral defeat for the first time in 116 years. Labour is six seats from victory on the 70-strong council.
Mr Major painted a glowing picture of an economy under control. Inflation had been below 3 per cent for 14 months, unemployment was falling and growth was double that of other Western European nations.
He dismissed suggestions that Croydon's Tories might have the best policies and past record in the world, but they were saddled with a national party and leader trailing badly in the polls. 'If the polls were to be believed, I would have lost the last general election,' he said. 'I know of no European nation who wouldn't give their eye-teeth for the economic prospects that lie in front of the United Kingdom.
'People are recovering from a very bruising recession. We had to pursue policies that were right in the long term, but were unhelpful in the short term. I am not interested in short-term booms, I am interested in establishing the right sort of economy where business can prosper and grow,' Mr Major said, to a chorus of agreement from Croydon candidates and party workers.
David Lipman, councillor for South Norwood for the past eight years, maintained national issues had not been raised on the doorstep in campaigning for the elections on 5 May. 'Croydon people are not idiots,' he said. 'It's a local election and Croydon has always had low rates and has offered a good service.'
Elsewhere in the Hilton, sitting under the palm trees or eating in Ike's Diner, the patrons were supportive of Mr Major.
Peter Whitehead, owner of a Croydon-based transport company with 60 workers, said there had been a great deal of investment in out-of-town locations despite the recession.
'We have just invested in a new freehold property. A lot of jobs have been created, which have taken over from those that have moved away to cheaper areas. I think Mr Major has had a very tough time but he has come through,' he said.
Such words would have been music to the Prime Minister's ears, but he was whisked away to a similar gathering of the party faithful in Putney, south-west London, without meeting any members of the general public.
Later, Mr Major paid tribute to the courage and dedication of the murdered police detective Jim Morrison, who was stabbed to death as he chased a handbag thief when off-duty. The Prime Minister unveiled a memorial in the Aldwych, central London, on the spot where DC Morrison died in December 1991, saying the plaque would stand as a lasting tribute to the officer's bravery.