Manchester Airport spokesman John Greenway said initial inquiries revealed the boy passed through border controls and ticket checks without documentation on Tuesday just by closely tailing families. He was discovered only after passengers raised concerns mid-way through the flight.

Manchester, in northern England, is hosting several Olympic soccer teams playing at the city's famous Old Trafford stadium.

The airport and the airline, Jet2, have suspended several staff. Transport Secretary Justine Greening has demanded a report.

"We'll be looking to rectify as soon as possible, making sure it doesn't happen ever again," Greenway said.

The airport emphasized the boy did not pose a security risk.

"He did go through full security screening. So he didn't present a threat to himself, to other passengers, to the aircraft," Manchester Airport Director of Communications Russell Craig told Sky TV.

The boy was escorted back to Manchester on a return flight and reunited with his parents on Tuesday evening.

Spokesman Greenway said the airport has not beefed up security to the level of the international airports around London, which are seeing the bulk of visitors for the July 27-August 12 Games.

"But it's the busy summer period for us so there will be additional security staff on anyway," he said.

Speaking on Sky TV, Transport Secretary Greening said:

"We place an incredibly high premium on making sure that security checks are being done and obviously I'll be very keen to understand exactly what happened in that case." (Reporting by Sophie Kirby; Editing by Sonya Hepinstall)

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