If I claim disabled widows benefits on my US husbands work record in the USA is it taxable in the UK?

I have been told that I have an entitlement to claim as a disabled widow on my deceased American husbands work record (social security number). He served 21 years in the US military. I am British, now living back in the UK. I had a social security number and green card in the US but only worked there for a short period and have no work record there. Would I pay tax on any money I received and if so who to. Would it be worthwhile making a claim?