Deity entering principal UK island in attempt to annex? (4)

I believe the answer is:

grab

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'to annex?' is the definition.
(thesaurus)

'deity entering principal uk island in attempt' is the wordplay.
I cannot quite understand how this works, but
'deity' could be 'ra' (Ra is an example) and 'ra' is located in the answer.
This explanation may well be incorrect...

Can you help me to learn more?

(Other definitions for grab that I've seen before include "Impress" , "Seize rudely" , "Brag about seizure" , "Grasp roughly" , "Take quickly" .)

I've seen this clue in The Times.

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