Leak on plastic pipe feeding radiator

[rubble2]

Apologies if this is a daft question but here goes.

About five years ago we had the downstairs bathroom refurbished and in the process the plumber rerouted the pipework to the radiator using plastic pipes. I have just had the radiator off to redecorate and on refitting it there is a slight leak where the pipe joins the valve. Question is, how are the plastic pipes connected to the valve? it looks like a standard compression connection, is that possible? if there is damage to the pipe causing the leak how can I get round this? (in the past with copper tube I have cut it back and extended the tube with a soldered in line connector) There doesn't seem to be enough give in the tube to pull it up and re make the connection. Any help gratefully received

 

[clf-gas]

Just give the compression nut a nip

 

[BingoBongo]

yes its a typical compression fitting.make sure its not running down from the packingwhere you turned the rad off.failing that take it off ptfe tape it and tighten.make sure theres an insert in it also

 

[rubble2]

Thanks for the help chaps, now sorted