It was a record-breaking, busy day for Heathrow on Monday as Olympic athletes began arriving in London . But over the weekend, senior border officials revealed that terror suspects had been allowed into the country, again leading to questions over Olympic security.After years of planning, and months of practice, the Olympics Games are finally here. The first test of success falls on the shoulders of Heathrow, as the world’s busiest airport faces its busiest day ever. Athletes from 204 countries have begun arriving in London. The airport is receiving two passengers every second. 236-thousand by the end of the day. But there’s been controversy behind the fun and games. Over the weekend senior border officials said that terror suspects have been let in to the UK without the necessary security checks. Inexperienced new recruits deployed to shorten queues are reported to have let in up to five suspects in a day. Officials have said that this busy day at Heathrow “heralds the start of Britain’s biggest peacetime transport challenge.” It’s a peacetime challenge guarded by thousands of soldiers. And in 10 days from now, Heathrow will break its own record, it will be even busier, with a quarter of a million passengers passing through. They won’t want anymore leaks from inside raising concerns over security.