Hmmm. A lot would depend on cause, context and motivation - if the israelis were fighting for their lives and their country I wouldn't like to risk it as they'd have everything to play for and everything to lose. Similarly, if the Israelis were in Hitler's position in 1940 - looking over the Channel and poised to invade - they'd probably get as badly unstuck as trhe Germans did.
On current form, the Israeli air force would be primed to bomb only areas with significant Muslim populations so Brick Lane, Sparksbrook, Rusholme, Bradford, would be pounded to pulp by Day Three. Heavens above, we'd be putting up fake minarets in empty fields and watching the IAF waste its munitions on targets they've been so trained to zero in on that they couldn't stop themselves from attacking... (while, of course, important military targets went unbombed)
The Israeli army last fought a conventional ground war against a conventional enemy in 1973. They did brilliantly at it, but this is over a generation ago.
Meanwhile, Britain has fought and won wars in the Falklands, Sierra Leone, Kuwait, Iraq... we have recent and consistent history of winning.
Although as an old Tom, may I say I'd far rather have the Israelis on my side and pissing out, rather than on the other side and pissing back?