Mayoral candidates take note: London's economic success is in jeopardy if we don't sort out our transport infrastructure

Cramped like sardines, in a tube train moving at a pace that would be measured better in centimetres than in miles per hour, none of us passengers wore a smile yesterday. That journey, just four stops on the Jubilee line, seemed interminable and the collective irritation was tangible.

An hour earlier, a prominent and usually fairly calm corporate adviser specialising in construction had suddenly snapped into wild animation, barking at me: “London is Britain's only successful export. There's no manufacturing anymore. But the infrastructure is wrecking that brand. There's only so much that people will take, and Paris is sitting there waiting for them to move there. That's what you should write about.”

After that tube journey, I had to agree. London, which has pulled away from New York as the leading financial centre in the past five years or so, simply isn't working. There are so many problems.

Even if Terminal 5 hadn't opened in such a mess, the fact is that it has been built years after it was first needed. That terminal will only arrest the current capacity malaise. Within months, rather than years, it will become simply insufficient for the growing army of travellers.

Ditto a third runway at Heathrow. That should have been built years ago, and with the prospective mayors all lining up against it (see my “What's wrong with cheap flights to Krakow?” comment from 4 March) that runway might never be constructed. The four candidates should be ashamed of their shared short-sighted idiocy.

Talking of the candidates, all they seem to be wittering on about is bendy buses versus Routemasters. Honestly, what an inane debate. This election must be boring the hell out of the world's media: “What dull, quaint little Londoners they are.”

If they want to do transport, do the Tube. Asking around, I think the majority of Londoners are convinced that the underground service has got dramatically worse since late last year. Every day there seem to be delays and lines out of service.

Frankly, what's really needed is new lines. A one-stop connection à la Waterloo and City line is desperately needed between Canary Wharf and the City. A line taking some of the pressure off London Bridge, which is being overwhelmed by the More London Place development and is sure to hit a standstill when the Shard is built, is essential.

On national rail, it has all gone eerily quiet over Crossrail. Even if you are not of a religious disposition, it's well worth taking a punt on a silent prayer that Crossrail isn't somehow falling foul of the credit crunch.

A good start would be to get rid of some overland-train ticket barriers. Anyone whose daily commute ends at Blackfriars station, the gateway to the City and West End, will tell you the early morning hell of getting out of there. With its small entrance, the place was never designed for that many people and definitely cannot cope with the delays caused by Oyster cards not working and people misplacing their tickets. The amount of time it takes to get out of that station is ridiculous.

Yes, there is a risk that some people will take advantage and not pay - but a greater danger is to risk testing the patience of London professionals any further. They will leave sooner or later.

And a few Routemasters ain't going to be enough to get them to stay.

PS Interesting that Land Securities has put its stake in Birmingham's Bullring up for sale. Already they are selling the Trillium business. Could it be that the Bullring is testing the waters to see what prices they could get for the other two businesses, the London and retail real investment trusts? Until now management has said the plan is to simply demerge these two businesses. Don't be shocked if they sell up instead.