score:7
Neither the metal detectors, nor the full body scanners currently in use at UK airports are designed to measure or detect body temperature. However infrared camera systems designed to do so are fairly simple to install, and are known to be installed at various airports worldwide to catch fever sufferers. On a far simpler level the same kind of non-contact technology is also being used in handheld thermometers.
At the moment this is primarily targeted at travellers from the highest-risk areas (i.e. mainland China). Since known cases in the UK are still extremely rare, it's likely you would be recognised as having a high probability of having some other virus (they are rather common after all). Having said that, the situation is subject to change, so keep following the news, and consider the worries of your fellow passengers (e.g. carry tissues & hand sanitizer)