Locksmith needed

Can anyone recommend one in SE1?

Depends what you want one for. If you want to have new locks fitted, then I highly recommend Banhams (though they're not in SE1.). They're not the cheapest, but their locks are very secure, and their service is good. They replaced my locks and put in hinge bolts for me about a year ago, and they didn't try to sell me bits I didn't need, and it was all done very quickly, neatly and tidily. Also, I locked myself out of my flat the other day, and they got someone to me within three quarters of an hour, and he got me into my flat in 10 minutes. Their details are here: http://www.banham.com/

Worrall's in Great Suffolk Street:
http://www.gworralls.co.uk

Thanks for the replies - I will now pass on to my sister who is the one in need. (It is for a new lock to be fitted).