LONDON, Dec. 30 -- Oliver Letwin, British Prime Minister David Cameron's policy chief, has apologized for any offence caused by "deeply racist" remarks he made about the black people in London in the 1980s, local media reported Wednesday.

Newly-released documents from the National Archives show that Letwin claimed "bad moral attitudes" were to blame for riots and social problems in the chiefly black inner-city areas of London.

Letwin has been Chancellor of the Duchy of Lancaster since 2014. He wrote the remarks in a 1985 memo, co-authored with future member of the Parliament (MP) Hartley Booth, to then Prime Minister Margaret Thatcher, days after the Broadwater Farm riot in north London.

"The root of social malaise is not poor housing, or youth 'alienation', or the lack of a middle class," they wrote in the document.

"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," the memo said.

"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," it added.

The remarks sparked a public uproar, and politicians from opposition parties and civil rights groups have urged Letwin to apologize for the "racist" comments.

Chuka Umunna ,a Labour Party MP, said Letwin's attitudes were "disgusting and appalling".

"The authors of this paper illustrate a complete ignorance of what was going on in our community at that time, as evidenced by their total and utter disregard of the rampant racism in the Met Police which caused the community to boil over - there is no mention of that racism in their paper," he said.

"The attitudes towards the black community exhibited in the paper are disgusting and appalling. The tone of it in places is positively Victorian," he continued.

In a statement, Letwin said he apologized "unreservedly" for the memo.

"I want to make clear that some parts of a private memo I wrote nearly 30 years ago were both badly worded and wrong," he said.

"I apologize unreservedly for any offence these comments have caused and wish to make clear that none was intended," added the statement.

Letwin had previously served as Minister of State for Government Policy from 2010 to 2015.

He has been given overall responsibility for the British Cabinet Office and became a full member of the cabinet in the Conservative government following the 2015 general election.