Boris Johnson didn’t get where he is today by thinking small, and that’s one of the reasons Londoners are lucky to have him.

From bringing back the traditional double decker bus to providing a fleet of “Boris bikes” for hire, London’s mayor has made his mark on the city he leads.

And lest anyone accuse us of bias, we should also mention former Labour mayor Ken Livingstone’s willingness to pursue bold policies like the congestion charge – one of those ideas that everyone opposes at the time only to turn around a year later and admit he was right all along.

But it’s the great blonde bombshell who’s on our minds today, as we consider Boris’ plan for a new airport, situated conveniently in the Thames Estuary or, as it’s known to most of us, the North Sea.

Nobody can say he lacks ambition. The airport known as Boris Island would be built on an artificial landmass – actually a peninsular rather than an island – somewhere off the Kent coast.

In this way, Mr Johnson hopes to solve a dilemma. His problem is that the south east clearly and urgently needs more aviation capacity, but nobody in the south east wants a new airport, or even a new runway at an existing airport, on their doorstep.

So building an airport in the middle of the sea might look like an elegant solution. We, however, have an even better one.

Birmingham has an excellent airport which already serves nine million passengers – and this number could be doubled relatively easily.

That’s not to say that Birmingham’s expansion plans are a small undertaking, but they’ll come into effect much quicker, more easily and at lower cost than Mr Johnson’s proposal. The Government’s plans for a high speed rail line already acknowledge the role that Birmingham Airport plays, and can play in the future, with the inclusion of a Birmingham Interchange station for high speed trains near the airport.