At lunchtime on a Monday, Canary Wharf is a hive of activity. Workers in navy suits swarm in to salad bars and eat sandwiches on benches, the sunlight glinting off the towers of steel and glass above.

Mentors of Level39, the tech incubator space in Canary Wharf's tallest tower, were left confused after they found themselves locked out of the exclusive space with no explanation. Several Level39 ...