Throughout the country in March, April and early May we all suffered horrendously cold easterly winds - I am in Cheshire, and we all had to sow/grow our Toms in unusual conditions.
I am fortunate in that we have a large heated Conservatory and an understanding wife, in late February on returning from winter hols I sowed the Toms (Unwin`s Gourmet and Gardener`s Delight) on the 15th. They germinated in 10 days and pricked-out beginning of March. I have a 6x6foot GH in which I object to putting on the heating until very late March/early April because of the cost of electricity so they had to stay in 4 inch pots in the Conservatory for much longer than usual.
Since 1999 my wife and I have kept a diary for the garden and with following details of the past years, come June, I find that my Toms are only a week or two behind the average. They have 4-5 trusses of flowers, 5 ft. high and green fruit, the heating is OFF with night temperatures in the GH of 50-55 degrees (I leave you younger ones to work this out in your European numbers!).
I still hope to pick ripe Toms in another 4 weeks (mid July) and then compare them with past crops. We all have to compensate from one year to another due to our "fabulous" climate but if you can compensate to some degree, you can still achieve a high production.
YES, my Toms will probably cost £2.00 per Tom!!!! but what satisfaction. Better than tasteless supermarket rubbish and all grown by you!