Keep calm and move to Berlin

After the Brexit referendum a van toured London with a billboard saying, "Dear start-ups, Keep calm and move to Berlin."

Right now UK start-ups are investors' darlings. They attracted £3 billion in investment last year - double what they received in 2016, and four times what French and German start-ups received.

There are worrying signs though. The number of funding rounds has decreased by 20% a year for the past two years, and rounds average about $1 million - half the size of French and German rounds. Our funding rounds focus on seed-corn funding for experimental start-ups, with generous tax breaks for investors, while on the Continent the money tends to go to businesses that have already proved their business model.

It is arguable which method is better - fund a lot of nascent start-ups and hope a few make it big, or help successful start-ups to grow into real businesses. It is unarguable that both strategies require a talent pool of skilled workers.

Germany now has more developers than the UK. The number of science, technology, engineering and maths graduates is rising rapidly in the Germany and France while the UK has a shortfall of 40,000.

Only a couple of years ago we could have shrugged our shoulders - if we need them they will come. Talent from all over the EU would fill the jobs, boosting our GDP and paying taxes without costing us a penny in training. Investors would want to join the gravy train, and funding would keep going up.

Instead, post-referendum the UK government - and Mrs May in particular - is intending to clamp down on immigration. We will no longer be able to make up our staffing shortfalls - in nursing, in agriculture, in technology firms - by poaching from overseas.

The immediate irony is that we have nearly full employment, so this is a political policy rather than a practical or economic one. However, if we don't want foreigners coming over here and taking our jobs, then we need to do them ourselves. That is all very well if we can find 40,000 people with the necessary technical skills, otherwise those start-ups will have to go where the talent is.

Keep calm and move to Berlin - who says the Germans don't have a sense of humour?