Cut slots in a piece of 22mm copper pipe and flare the ends.
Unless you have a short length of 22mm copper lying about, I'd either by a 1m steel tube or get the proper tool.
+1 for both comments.
The copper tube method works fine and when I tried to buy the proper tool the internet bike shop emailed me back to tell me not to waste my money if I had an appropriate length of copper available. Owing to just jhhaving the kitchen redone I did have such a thing. Mind you the kitchen cost me best part of £8k so it was hardly a cheap solution. If I'd had to buy the tube I'd have gone for one of the other two solutions depending on availability.