Best way to refit mismatched p trap

Hi All

I have to refit a plastic p trap (1 1/4") with compression joints. The problem is that the sink tailpipe is 1 1/2", whereas the other end of the p trap has to go into a 1 1/4" plastic compression joint. At the moment when I refit the p trap it leaks at the sink end because the p trap pipe size is too small.

How would you guys rectify this? Is using silicone around the pipe of the p trap the easiest way, or is there a better way to do it? Maybe if I tried buying a 1 1/2" rubber O-ring for instance.

Any thoughts or comments much appreciated.

Many thanks

Accelerator

I don't understand which way round you are - use the right size for the sink, 1 1/2" (unless you mean basin, 1 1/4") then use an adaptor to fit to your drainpipe.