The butler did it, of course, or so the police charged yesterday in one of the biggest and grisliest mass murders in British criminal history.

Archibald Thomson Hall, a smooth-talking Lothario who has butled for some of the richest families in London, was accused of strangling his former employer, the wealthy Walter Scott-Elliott.

In addition, Hall was charged with killing a gamekeeper, David Wright. He had looked after the pheasants on a Scottish estate next door to Scott-Elliott's and may have known too much.

This is only the beginning. Police have yet to charge anyone for strangling Mrs. Scott-Elliott, Hall's convict brother Donald and Donald's common law wife, Mary Coggle or "Belfast Mary" as she was known in the pubs around Kings Cross.

In a sheriff's court near Edinburgh today. Archibald Hall, the butler, was handcuffed to his alleged accomplice, Michael Anthony Kitto, 39. So far, Kitto is accused only of helping Hall stomp on the throat of his 82-year-old employer, and then strangle him with a scarf.

Neither man pleaded to the charges in what has become a script suited for an Agatha Christie novel.

British police are normally reticent about the details of a criminal case. But this one, stretching from London to the Scottish Highlands, has touched off such keen rivalry between London's Scotland Yard and Scottish police that much of the story - as police see it - has already emerged. It is said to go like this:

Scott Elliot - Eton, the Coldstream Guards, five years in the House of Commons as an obscure Labor Party member, rich East India merchant - lived quietly with his second wife, Dorothy, in a lavishly furnished apartment in the fashionable Chelsea section of London. He was 82, she was 60 and the pair moved easily from their estate in Scotland.

Their Meissen china, porcelain and thousands of dollars worth of antiques in that Chelsea flat were apparently too much for butler Hall. White Hall's brother was still serving time, his common law wife, Mary Coggle, became the Scott-Elliot's housekeeper. Coggle was a bit of an actress, fond of wearing wigs and dashing out with the younger men, and she played the part well for a while.

Twelve days before Christmas, the two servants struck. Mrs. Scott-Elliot was strangled in her apartment and her body was shoved into the trunk of a car. Her husband was given a drug. Coggle was draped in an expensive mink and seh, Hall and the drugged Scott-Elliot drove off together in the same car.

Their bizarre ride took them nearly 500 miles north to the Scottish Highlands. Along the way, Hall sold off about $6,000 of Scott-Elliot's antiques. Coggle, posing as Mrs. Scott-Elliot, authenticated their ownership. Scott-Elliot's credit cards paid for lodgings and meals.

Coggle never lived to enjoy the spoils. Her body was found on Christmas Day near a Glasgow road. She too has been strangled.

The Scott-Elliots traveled so much that nobody reported their disappearance. But on Jan. 15, a hotel keeper in a hamlet near Carlisle somehow did not like the looks of two men who were dining at his table. He called the police who began questioning the pair, Hall and his alleged accomplice Kitto, and looked into their car.

In the trunk, police found the chloro-formed body of Donald Hall, 37, who had been strangled with a plastic bag. He had just come out of prison an presumably asked his brother some awkward questions about Coggle.

Police dogs were soon prowling the frozen wastes of Scotland. Scott-Elliot's body was found on a vacant lot near Inverneess, his wife's in a stream near Perthshire. The badly decomposed body of the murdered gamekeeper, Wright, was also discovered. All this, in any event, is what police say happened.

And now, in the quaint phrase used here, Archibald Hall and Kitto are "helping police with their enquries."