Commonwealth is a grouping of countries who have been part of British empire at some point in time. In mid 20 th century many Asian -african countries attained freedom from British crown & gone for democratic political setup. The idea behind forming commonwealth group was to get benefited from common legacy which has also influenced present polity & governance of these countries.
Relevance today:-
Commonwealth was never a very strong international grouping with well defined objectives like NATO, EU, ASEAN etc. That too its membership was also optional & its inception was being seen as a grouping seeking goodwill of fellow partners.
In present scenario when economies are very much open & all the countries are not shying away from collaborating with any other country to secure their interests , new groupings are being formed with very clear objectives, such groupings have their own constitution & legal liabilities etc , in such a situation CWG looks like a slightly vague concept hence less relevant.
Importance for Britain:-
1. Quest for new market:-
CWG counties are growing economies , with big population & sizable middle class population. Britain definitely wants to tap this market.
2. Similarity to British model of Democracy:-
Most of the countries formerly under British crown has gone with British model of governance, law & judiciary, which is a plus point for Britain to enter such countries & form ties.
3. Cheap workforce:-
CWG countries can offer cheap labor to otherwise aging Britain.
CONCLUSION:As 19 th, 20th century moved around Europe & USA respectively it is said that 21nd century belongs to Asia-Africa . Britain definitely want to revive its old connection with these CWG countries,mostly membering Asian and African countries.