No, you CAN defend yourself when your home is burgled while you're at home. As Saracen previously mentioned, it depends on whether the force you use is "reasonable". The question of what is "reasonable" is both a matter of fact and with consideration to the householder's state of mind.
For ex. if the burglar came armed with any tools such as crowbars or even just a screw driver etc. and the householder saw this and is fearful for his or his family members' life, it would be reasonable for him to arm himself and confront the burglar. Should the burglar then attack the householder and is killed by the householder in the process, then that would be in reasonable self-defense. However, if, as in the Martin case, the burglar turns and run and the householder gives chase and kills the burglar then the force use would be deemed "unreasonable". The key here is not only the householder's state of mind, but also whether the "escalation" of force and of arms is
porportional and therefore reasonable.
So it is not enough simply for the householder to claim to be in fear for his or his family members' life and safety. The facts, both in testimony and from forensic evidence, need to born that out. But where the forensic evidence and reconstructed sequence of events are indeterminable and in doubt, the chances are reasonably good that the jury will find in favour of the householder, particularly as the standard of proof in such cases need to be beyond reasonable doubt, which is much higher than on a balance of probablities in civil disputes. But even then the CPS (Crown Prosecution Service) may still try their luck if they feel the chances are good for a successful prosecution, based on available evidence. It's a judgement call.
I should be charging for this....
....but then I'll be liable.
So here's the disclaimer: Should any Hexus members find themselves in similar situtions - consult a qualified legal professional.