Nearly 140 members of the House of Lords have not spoken or asked a question in Parliament for at least a year.
The presence of dozens of silent peers, who are all entitled to the privileges of membership, is one of the arguments used to counter those who say the House of Lords works well and does not need reform.
For some peers, the Lords is a convenient club in the centre of London, with free parking, free phone use, a vast library and subsidised bars and dining rooms.
Others are members of the House of Lords in name only, because they have not set foot in the building for years, either because they are too old or have lost interest, but there is no mechanism that allows a peer to resign.
Nick Clegg, Britain's Deputy Prime Minister, is bracing himself for a long battle when he sets about trying to reform the Lords.
A draft bill published last month suggested that the upper house should be reduced to 300 members, 240 of them elected.
More than a third of the 137 "silent" peers - more than one in six of the total membership of 789 - are older than 80. Others can be assumed to have stayed away because they have full-time jobs.
Baroness Falkender, 79, a powerful figure in Downing St when Harold Wilson was Prime Minister, still casts her vote in the Lords, but there is no record of her ever having made a speech since taking her seat in July 1974.
Tory peer Tim Bell, Margaret Thatcher's former PR adviser, began his most recent speech in the Lords, in February 2008, by admitting: "I rarely speak in the House". The authoritative theyworkforyou.com said it was the first time he had spoken in the Lords in six years.
"Many peers take our job of amending laws and controlling governments as seriously as the public expect," the Liberal Democrat peer Lord Oakeshott said yesterday. "These hundred-plus sleepy peers should wake up or move out."
The rules say those who are too busy or too ill to take part should say so and take "leave of absence". Only 21 out of 137 silent peers have done so since last year's general election.