It was a complete shock to the crews of three narrowboats who were leaving the Inland Waterways Association's Canal Cavalcade out of Limehouse and up the tidal Thames when they were hailed from officers on a police launch and told to heave-to as they were going to be boarded and searched!

The boaters were told that there was concern that terrorists could hijack a narrowboat at gunpoint, place a large bomb on board and detonate it under Tower Bridge or alongside HMS Belfast or elsewhere on the Thames tideway.

The police however soon discovered that the boaters were bona fide, had not been hijacked and that there were no bombs on any of the boats.

James Fowler, on one of the boats related:

"It was the hell of a shock when this police boat came tearing up to us and told us that we were being boarded, we just didn't know what to think.

"It was the first time we had been on the tide, and we were all on edge anyway being thrown about by the big trip boats as they went flying past, we thought it was a drugs raid or something."