There are different answers depending on when the separation occurred and whether there were any conditions placed upon the gift when given. 

Under The Law Reform (Miscellaneous Provisions) Act 1970 Section 3(2) it quite clearly states:

‘The gift of an engagement ring shall be presumed to be an absolute gift; this presumption may be rebutted by proving that the ring was given on the condition, express or implied, that it should be returned if the marriage did not take place for any reason.’

Therefore, if the separation takes place after the parties marry, then the law is clear - the engagement ring was an absolute gift and therefore the receiver shall retain the ring. 

However, if the separation takes place before the parties marry, then it will depend on whether the engagement ring was given on the condition that the marriage must take place. 

Having been engaged myself and having many friends, colleagues and associates who have also been engaged, I must say I have never heard of anyone proposing with a beautiful engagement ring whilst also putting on the proviso that 'if this doesn't work out and we don't get married, I will want the ring back'. 

My personal view is that a condition such as that would only be expressed or implied if the engagement ring was a family heirloom or similar. 

If an agreement cannot be reached between parties, an application can be made to the court wherein the court would look at all the circumstances and decide whether it was expressly stated as above, that the ring be returned or whether it was implied that the ring should be returned if the engagement broke down. 

Bespoke advice would be needed before litigation is pursued, so that you know what your options are and whether, on a cost analysis basis, any claim should be pursued. 

If advice is needed, please feel free to contact me or my team on 0121 212 7417.