money sums + singular/plural

[Perho]

Hello,

I was thinking that money sums take the plural, e.g. in sentences as “50 pounds are paid to...”. However, today I came across this sentence:

£1,000 was paid to Emily.

Now what is correct (and why) ? Logically, I was thinking that as the numbers are higher than one, they must stand with the plural. I can’t find anything about that in my grammar book (Longman).

£1,000 was paid / were paid. ?
£50 is / are a large sum ?

Thanks in advance for any helpful comment.

[Alan]

Sums of money are always treated as singular in contemporary usage (Fifty pounds WAS paid, etc.)