According to the 2011 Census, Peterborough still has an overwhelmingly white, British population....84.4%.
83.7% have English as their main language, and 80% were born in Britain.
In mid-2014, the population of Peterborough was approx 193,740.
So....perhaps all those 10,000's of white British people don't go to Pubs often enough any more ? Logic would say that if the did, and business was booming, then there would still be lots of thriving Pubs.
Pubs have been closing down for years. In my village, in the Swansea Valley, 3 of the original 8 pubs have changed into a Vets, an Italian Restaurant and one is just boarded up and has been for 5 years. Very few Polish locally, so they can't be blamed.