Just thought I'd get it in before the Scottish/Northern Irish/Welsh/Cornish/any other British contingent of the Massive put the boot in.

If you're talking about RP (Received Pronunciation) Sophie Ellis Bextor is the only one that springs to mind and "that bird from the Art Of Noise whose name eludes me" helped them do very well for themselves by being sampled by the Prodigy. Not really singing though.

Like DTHP above, I assume you mean RP and the one that springs to mind is Sarah Nixey either on her her own or with Black Bow Recorder.
If you really mean a British accent then there are loads, The Lovely Eggs are clearly British, as is Kate Rusby, Nick Lowe is cleasrly British from his singing, then there's Glasvegas.. I'm sure the list is very long indeed.

TT sings in an impeccably English accent. So does Pye Hastings. And Richard Sinclair. And Robert Wyatt. Hmm, trend forming here.

Sorry, it's all the same to us convicts and colonials, in that I mean an accent that is recognisably from the UK as opposed to the US.

So can I get this straight - British includes Irish, Scottish, Welsh - English means England - hmmm, of course.

(retrieves garment left at door)

anyone singing in anything but their own accent gets laughed at.

is always well enunciated. Lilly Allen and Kate Nash have very clear English accents when they sing - even if it isn't RP.

then surely here are three pretty strong and distinctive ones:

(Shack - Comedy)

(Ian Dury and The Blockheads - Billericay Dickie)

(The Fall - Hit The North)

Shaun Rider always sings in pure Manc. If you can call it singing (pronounced with a hard middle g).

Surely that sounds like this?

English accent thick enough to spread on yer stottie cake:

And I can't believe this lot haven't been mentioned yet!

You want a posh English accent? You want enunciation? You want vocals so dead pan they make Neil Tennant sound like some attention-seeking X Factor caterwauler?

Ladies & Gents, I give you Deborah Evans-Stickland of the Flying Lizards, giving a performance of Sex Machine that the Godfather of Soul could never have imagined in his freakiest dreams. Brilliant!

"Downtown" is in the Top Ten Greatest British Pop records ever made. If you disagree you are wrong.
Also one of the greatest fade outs in pop,The Trumpet is brilliant.

seems to exclude the way language is used in large areas of "Britain" today. That language is a cross pollination of Estuarine/Afro-Caribbean/Asian and flavored with indigenous local accents. But broadly speaking, Bristol, Birmingham,Manchester and the good ship Lahnd'n share similar vocabulary and tropes.

Sometimes, this is borderline comical as in an exchange I heard in a bar in Bristol recently where two twenty somethings were earnestly engaged in conversation about shoes, with one employing the immortal phrase

"man, dem is like well nang trainers innit blud" except in a Bristolian twang a la Little Britain's Vicky Pollard.

As on the streets and in the homes of "Britain" so it is in the music and you don't have to delve too far into Grime or Dubstep or Brit Hop to find examples. Mainstream music from Mike Skinner to Tinie Tempah to Cher Lloyd is full of Its presence.

For example, here is Mr Dizzee Rascal and "Stand Up Tall"

All hail the sexy queen of bland with one of her two decent songs!

Sarah Cracknell does not exactly sound like she born deep in the heart of Texas...

I'm a sucker for sexy strong Scottish sirens. Lulu from the same era as "Our Pet" is still belting 'em out and KT Tunstall's whisky-tinged vocals earned her a hand crafted guitar from distiller Talisker. But if it's enunciation you want then Annie Lennox's crystal tones hit the spot every time.

that Charlie Chaplin wrote This Is Your Song.

Her none-more-Roedean and completely spiffing version of Sgt Pepper's Lonely Hearts Club Band. Jolly good show!

[NOEL COWARD - Mad Dogs And Englishmen]

I always admired Tommy Steele for singing in his natural accent and not trying to emulate Presley like all the others at the time. And I've always been a huge fan of Anthony Newley too for the same reason..

Just released in Ireland, this version of Downtown features the woman herself on backing vocals with the Saw Doctors...

Is youz sehying dat Prof Green doesn't speak to da massif is a pwopa English accent? Das rad man. Sick. Innit...

God I want to slap him.

SPEAK PROPERLY YOUNG MAN. You are 27 years old from Hackney (even that's subject to debate) - not a primary school kid from Brooklyn.

Anymore.

Nearly all these examples are from people who made their name and most of their records (or at least, the good ones) well over twenty years ago.

So who sings in a British accent nowadays? I know that Dizzee Rascal's accent is as British as Sue Lawley's, but as I understand it that wasn't the thrust of Mousey's original question.

Sophie E-B, Sarah Nixey and Dido, yes. Amy MacDonald sounds pretty mid-Atlantic to me in that clip. Any more for any more?

electing Roger Whittaker

This might be why the vowel sounds tend to sound American.
Our brains have a speech centre and singing centre.
People who have had strokes can learn to talk again by singing.

I'm a singer who tends to sing a lot of soul. I'm also reasonably
well spoken. When you hear me sing you'd be in no doubt that I was English
but I certainly wouldn't go out of my way to pronounce things in an English accent. I have tried in the past but it just sounds twee and camp.
Try singing "yeah baby" in a soul style with an English accent...Doesn't work does it!
Doesn't feel natural to sing either.

on hearing She Loves You for the first time in 1963, turned to Paul and said "That's very nice son, but there's enough of these Americanisms around. Why couldn't you sing 'She loves you, yes, yes, yes?'"