They stopped checking at airports because it proved to be ineffective, most of those with temperatures didn't have coronavirus and corona sufferers showed no signs of having it.
Just because another country does something different, indeed if every country does something different, it doesn't mean they are right.
I think all these comparisons with other countries are invidious. This table shows that all things considered we are doing better than many other comparable coutries in Europe with similar populations www.worldometers.info/coronavirus/
Ebola had a 90% death rate. Count our blessings with Coronavirus.
To think that London, or anywhere else for that matter, does not belong to any one demographic