http://news.bbc.co.uk/1/hi/england/london/6329125.stm
It seems the latest craze now is .. mugging cyclists as well as car jacking.
Very difficult to advise . If in a car .. keep the laptop etc out of sight - locked in the boot.
On a bike?

.. bit more difficult to address as not many options open if you have a lap top which you use at home and for work. It would be insensitively glib to say "leave lap top secured at work" or whatever..
I can only advise really to keep to well frequented routes.. be vigilant to any situation .. and try to ensure you make some eye contact with the other road users in their cars.
I know that I read of one story in which the cyclist was pushed under a 4x4. He stopped and helped the cyclist - as an automatic human reaction.
But these stories rather highlight a very sordid turn for the worse in our society and we police really find this sort of mugging difficult to resolve. I can only ask for any witnesses to such events to come forward and report what they saw - and to the cyclists and CTC .. please approach us .. I am sure that together we can brainstorm a reasoned and logical safety led code to try to protect our cycling commuter "cousin" road users.
Not an easy one to resolve - especially in London where average road speed is 7 mph and cyclists manage a mere 13 mph .. compared with the double and more up here.
and NO..

. we want to keep our North special to us Northern folk - by 'ecky thump ,, and waye eye eye mun!"

!

We don't want southern riff raff up here - betting on whippets, ferret races .. trying on our clogs, cloth caps and scoffing suich Northern delicacies as jellied eels, tripe and onions, black puds and "gettin in our wayyyyy!" By 'Eck
But .. as ex Met officer down "sarf" .. PLEASE liaise with the police London CTC and cyclists. We up "Norf" are prepared to listen and work with you on this.. though we don't thankfully as yet have such reports of such wanton violence. But we want to be prepared for any such eventuality.. so I'd ask any CTC lurks or C+ lurks to help set balls a-rolling on this one..
For record .. very few on this site "hate" cyclists. All seem to want a valid road safety policy for all. No one really wants abolition of speed limits.. but rather a return to - cough - professional discretion and an end to nit picking silliness.
We (Paul, Swiss family and most on this site) respect ALL road users. I f any of our lurks from cycling fora and s/cam pratnerships or Roadpeace or BRAKE can suggest the embryo of an idea which we can then develop to a "full term baby and progress it to mature adulthood" - I think we make a stand for the bettering of our society and its return to refined and cultured behaviour patterns.