Newly released Government papers shed fresh light on politics in Margaret Thatcher era

Mr Letwin – then an adviser in Margaret Thatcher’s No 10 policy unit – poured scorn on claims that the disturbances were the product of urban deprivation, saying white communities had endured such conditions for decades without rioting.

He also dismissed proposals by Ministers to foster a new class of black entrepreneurs, saying they would simply set up in the “disco and drug trade”. The riots in autumn 1985 were among the worst disturbances to hit mainland Britain in recent times. They included serious unrest in the Handsworth area of Birmingham and Brixton, south London, as well the Broadwater Farm riot in Tottenham where Pc Keith Blakelock was stabbed to death.

The troubles were widely blamed on a combustible combination of high unemployment, slum housing, poor education and an atmosphere of bitter distrust between many young black people and the police.

In one document among the papers released by the National Archives at Kew, Home Secretary Douglas Hurd pointed to the underlying social and economic problems in the areas which had a “specific ethnic (notably black) dimension”.

But in an outspoken memorandum, written with fellow future Tory MP Hartley Booth, Mr Letwin – now the Cabinet Office Minister – urged Mrs Thatcher to reject the prevailing orthodoxy, insisting the troubles came down to “individual characters and attitudes”.

“The root of social malaise is not poor housing, or youth ‘alienation’, or the lack of a middle class,” they wrote.

“Lower-class, unemployed white people lived for years in appalling slums without a breakdown of public order on anything like the present scale; in the midst of the depression, people in Brixton went out, leaving their grocery money in a bag at the front door, and expecting to see groceries there when they got back.

“Riots, criminality and social disintegration are caused solely by individual characters and attitudes. So long as bad moral attitudes remain, all efforts to improve the inner cities will founder.”

Plans by Environment Secretary Kenneth Baker to refurbish crumbling tower blocks or by Employment Secretary Lord Young to encourage new black middle class entrepreneurs as a “force for stability” were not the answer, they argued.

“David Young’s new entrepreneurs will set up in the disco and drug trade; Kenneth Baker’s refurbished council blocks will decay through vandalism.”