Requires a lot more investigation. That socket has two sets of red and black wires. This means that either
1. It is part of a ring final, in which case where is the earth for the rest of teh ring??
or
2. It is a spur, with another spur coming from it. In which case
a) that is wrong
and
b) the spurred spur will also not have an earth.
and that socket has been repositioned some time in the past without the earth being provided.
Smells of a general handyman (or allied trade!) not knowing what they are doing.
... or, indeed, if it is part of a ring and there is an explicit earth conductor connected to that 'next' outlet.
However, as TTC has implied, there's no point in our speculating, because (as he said) some serious investigation (probably of the whole circuit) is definitely needed.
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local