I do not know if there is such a number but if you fill out a contact form click here you should in a few days(depending on how busy there are) receive assistance from the forum team.
I don't think there is a direct number,,,, There is a FTTC Infinity office in the UK but I think is a second line support type desk which won't take direct calls from customers.
Not only will they not take direct calls, India seem not to be able to transfer customers through, they advise they will send an engineer out, who then turns up to advise that as your speed is over 15mb, its acceptable, regardless if you have had 38mb for the first 3 months of service! dont think there is a 2nd line team in the world, let alone in the UK. The 2nd line resolution is give someone half decent service to get past the first 10 days, then turn it go to **bleep** and say "you signed an 18 month contract", ticket closed, first time fix.
If there was a direct UK number, then nobody would waste their time calling India.
Cant remember where I read this:
"Businesses that outsource customer care, don't save money. They tend to loose customers instead."