Lights Fused Again!

[craft1948]

Some of you may recall that the other week a bulb went in my main living room light fitting and fused all the lights. Straight after that the electrician came round and put me a switch on so's if it happened again all I had to do was flick the switch rather than put in some fuse wire.
Another bulb has just blown in the same light fitting and blown the fuse again.
I've had this 9 bulb light fitting for 2 years, why has it just started tripping the fuse when a bulb blows?

[craft1948]

Thank you all very much, I feel more reassured now.