Former Liberal Party leader David Steel has launched a stinging attack on modern day politics, hitting out at the role of spin doctors.

Lord Steel claimed the introduction of TV cameras in the House of Commons has turned Prime Minister’s Questions into a weekly “insult time” session.

The former Holyrood presiding officer also claimed the Scottish Parliament had gone down the same “adverse trend” as Westminster, saying “belligerence and stridency” are now commonplace there as well.

The increasing role of spin doctors – such as Boris Johnson’s adviser Dominic Cummings – is to be “deplored”, he insisted.

Lord Steel blasted the role they do, saying: “They hand out questions for MPs to ask and they daily bombard party activists by email with ‘lines to take’.

“Even I, as a  humble member of the Upper House, received daily doses of laundry lists of the alleged achievements of the Lib Dems in the coalition Government and a selection of press coverage – all favourable of course, nothing critical.

“The latest addition to these daily outpourings are suggested tweets to circulate.

“Fortunately I am not a tweeter, so I swiftly delete all these unread.”

He added: “All of this contributes to the diminution of individual expression or even thought in politics.

“Little wonder that the paid-up membership of the United Kingdom political parties is in decline.”

He spoke out as he made a plea for constitutional reform in the UK, calling for the House of Lords to be replaced with a “more useful” second chamber and for there to be a written constitution.

Lord Steel (left) and former prime minister Gordon Brown (centre) following the funeral of ex-Liberal Democrat leader Charles Kennedy (Andrew Milligan/PA)

Lord Steel was giving the Charles Kennedy lecture in Fort William,  in memory of the former Liberal Democrat leader who died in 2015, shortly after losing his seat in the House of Commons.

He said he wished he – like Mr Kennedy – had opposed the Liberal Democrats’ move into coalition with the Conservatives in 2010.

Lord Steel recalled how he had had dinner with Mr Kennedy on the eve of the 2015 General Election, saying he “confessed that I had quietly abstained on the issue of the Con-Lib coalition and wished in retrospect that like him I had opposed it”.

He went on to speak about the “reduction in standards” in politics, arguing the centrepiece Commons exchanges at Prime Minister’s Question Time have now “become Prime Minister’s Insult Time, with the two protagonists exchanging well rehearsed sound bites”.

Lord Steel said: “The rot set in when the Chamber became televised and Prime Minister’s Questions became the subject of weekly electoral entertainment rather than genuine scrutiny of Government.”

Holyrood has also suffered from “the same adverse trend,” he said, despite the chamber being set out in a semi-circular fashion as part of efforts to make clashes less confrontational

“That seemed to work for the first few years,” he said.

“But no longer – belligerence and stridency are the order of the day.”

The House of Lords should be replaced with a new body, Lord Steel argued (Victoria Jones/PA)

He argued the UK needs a “constitutional convention or commission to deal with the aftermath of our break from the European Union”.

Lord Steel said one of the key tasks of such a body could be “how to organise a more genuinely federal-type style of government throughout the United Kingdom”.

He added: “Here is where the reform of the House of Lords to create a more useful and democratic institution comes into play.”

Lord Steel proposed the unelected House of Lords be replaced with a new body of 500 members, “significantly less” than the current tally of more than 800 peers.

He proposed 400 representatives in this new chamber would be chosen “on the usual party political basis” being elected by MPs, and in Scotland MPs and MSPs combined, using proportional representation.

That would leave 100 members, who would also be chosen by MPs and MSPs but who would come from outside of the political parties.