Put a banana skin on the plant near the oldest truss.. The gas it gives off will start them off and once you have one coloured one left on the plant the rest will follow. Most ripe fruit especially a ripe tomato would work but not so easy to fix to the plant. Sounds weird but it works.

Oh! Thank You, I'll try that :o))
Ha! But since I put my question forward yesterday one tomato has now got some colour in it today LOL.

Amazing what asking for help will do! You could just leave that one to ripen until another one starts to colour. Self control is the
main problem now!

My Gardeners Delight only started ripening 2 weeks ago due to a very late start. Now I’m eating them every lunchtime. Love ‘em. Saw a recipe for bruschetta using plenty of toms and tried it - never again - absolute rubbish ( or is it down to my cooking ?)