The rattle of jackhammers and traffic gridlock welcome any visitor to London after the ides of March.

The UK financial year is ending: Spend your budget by April 5 or expect a cut, particularly if you’re in public works.

This year, the thud of suitcases locking and money swooshing down the Thames join this noisome mix. London’s non-doms and investors are in startled exodus.

The cause: severe new UK tax laws. And they’re empoverishing our industry.

Farewell and happy trails to foreign execs. They might have liked dining out in Notting Hill, but their stomachs can’t take paying £30,000 per annum to Her Majesty for the privilege.

Expect that damned nuisance called Plaxo to buzz you with new contact details. Which company will be worst affected? Perhaps BT’s Ben Verwaayen will quit his country pile in Haslemere and start commuting from Den Haag.

Denying the Chancellor his pound of flesh has also triggered a mini gold rush in ICT investment deals to beat new capital gains levies. So say my friends in London’s money business who aren’t packing their socks.

But I fear for early-stage British ICT firms that won’t easily find angel investors in the future. Unlike firms like Daisy Communications, Wavex, or Virtual IT that have progressed to the Deloitte Technology Fast 50 or achieved similar growth milestones.

Let the UK government now put a hand in its own pocket if it’s serious about Broadband Britain. Because it’s just pushed some major sources of inward investment violently out the door.

(And in case you’re wondering, nobody in Yankee Group’s UK offices is a non-dom.)