Speaking as one of the afore-mentioned boffins
The question you have to ask DBIS is this: how many boffins do you expect to leave the UK in search of better prospects?
We put up with the low pay, and the petty bureaucracy, in return for sufficient funding to do something interesting and then tell others about it. We build up networks of friends around the globe. And, if conditions become uncomfortable, we are highly mobile.
So, for computing: Seattle, the Bay Area, or Sophia Antipolis vs Manchester? Right now, what holds me back are worries about health insurance and the doubtful nature of my rusty French. If either country has the foresight to make me an offer, I'm interested.
All it would take to wreck UK Science and Engineering is for politicians in another part of the world to make us an offer we can't refuse. An interesting ploy for the USA, at the right time, would be to make a blanket offer to consider all UK scientists in disciplines of interest, short-circuiting current immigration red-tape. For France the immigration status is even easier to sort out, and the climate in Nice is attractive. So to the French minister I say: "Give me a modest salary, and the research funding I need, and I'll move tomorrow."
And besides, buying up another countries scientists is probably the cheapest way to undermine it's viability.
(And if you want an example of how to do science in a recession look at the Alvey Project in the early 1980s. The UK CS scene was transformed by this, and ARM is only the most significant of the many productive companies resulting from that decision.)
What has David Willetts got to say?