The euphemistic British-English phrase to be economical with the actualité is a variant of the earlier (and equally euphemistic) phrase to be economical with the truth, meaning: to deceive people by deliberately not telling them the whole truth about something.

The phrase to be economical with the actualité occurred, for example, in the column Notebook, by Rowan Pelling, published in The Daily Telegraph (London, England) of Wednesday 16^th September 2009 [No. 47,989, page 22, column 2]:

Hollywood greats were exempt from the ageing process. The golden age movie stars were permitted to be economical with the actualité about age and pretty much any personal information: the carefully cultivated mystique of Garbo or Hepburn was a crucial element of their glamour.

The phrase to be economical with the actualité was coined in 1992 by the British Conservative politician Alan Clark (1928-1999) during the ‘Matrix Churchill’ trial at the Old Bailey in London. The following explanations are from Clark knew tool exports helped Iraq arms effort, by Charles Oulton, published in The Independent (London, England) of Thursday 5^th November 1992 [No. 1,889, page 2, column 3]:

A FORMER government trade minister told an Old Bailey jury yesterday that he had known machine tools exported by a Coventry company had been used in the manufacture of munitions in Iraq.
[…]
Mr [Alan] Clark was called as a witness during the trial of three former directors of Matrix Churchill, an Iraqi-owned machine tool manufacturer, who are accused of deceiving the Department of Trade and Industry. […]
Mr Clark was asked by Geoffrey Robertson QC, counsel for Mr Henderson [former managing director of Matrix Churchill], about a meeting with the company in January 1988. […]
Mr Robertson said: “You knew the Iraqis were not using the machine tools for civilian purposes.” Mr Clark replied: “The current orders, yes.” Mr Robertson: “You knew the Iraqis were making munitions with them and the delegates at the meeting knew?” Mr Clark agreed.
Mr Robertson then asked why he had mentioned only the possible civilian use. Mr Clark replied: “It’s our old friend economical.” Mr Robertson: “With the truth?” Mr Clark: “With the actualité. There was nothing misleading or dishonest in making a formal introduction that Iraq was using the current orders for general engineering purposes. What I didn’t say was their use for munitions. It would not have been appropriate at a meeting of this kind to widen it from the stilted and rather formal language that I used.”

In an account of the same trial, that of three former directors of Matrix Churchill, published on the same day, Thursday 5^th November 1992, in The Guardian (London and Manchester, England) [page 28, columns 7 & 8], Richard Norton-Taylor explained that the question “With the truth?”, posed by Geoffrey Robertson, was:

a reference to the response by Lord Armstrong, Mrs Thatcher’s cabinet secretary, in the Spycatcher trial.

This refers to the ‘Spycatcher’ trial in the Supreme Court of New South Wales, Australia, in 1986, in which the British Government was attempting to prevent the publication of the memoirs of a former MI5 agent, Peter Wright (1916-1995). Giving evidence at the trial, Robert Armstrong (1927-2020), then Cabinet Secretary and head of the British Civil Service, referred to a letter cited as evidence in the following terms:

“It contains a misleading impression, not a lie. It was being economical with the truth.”

John Sweeney gave the following details in Whitehall economical with the truth about arms to Saddam, about the trial of three former directors of Matrix Churchill, published in the Observer (London, England) of Sunday 8^th November 1992 [No. 10,491, page 3, columns 6 & 7]:

Mr Clark explained the decision to omit any reference to weapons production as ‘our old friend, being economical.’
‘With the truth?’ asked Mr Robertson, completing the notorious quote from Mrs Thatcher’s Cabinet Secretary, Lord Armstrong, during the Spycatcher trial.
‘With the actualité,’ Mr Clark replied, finessing the mandarin’s enrichment of the language. Later, Mr Clark explained that actualité was French for ‘instant reality’.

Note: In fact, a translation of the French noun actualité could be topicality: in French, une actualité denotes a matter of current interest, a news item, les actualités, also l’actualité, denotes the current affairs, the news.

The earliest occurrences that I have found of the phrase to be economical with the actualité used without explicit reference to Alan Clark are as follows:

1-: From the column Commentary, by the British Conservative politician and journalist William Francis Deedes (1913-2007), published in The Daily Telegraph (London, England) of Monday 23^rd November 1992 [No. 42,742, page 19, column 7]:

WHILE sympathising with William Roache, whose £50,000 libel award from the Sun was far outstripped by the cost of his action, I think people should revise their ideas about suing the brasher tabloids for libel. It must surely be recognised by now that those who write tittle-tattle about figures in the public eye are often, in the phrase of the hour, extremely economical with actualité. Why must they be taken seriously?

2-: From a letter to the Editor, by a certain Peter J. McGunnigle, about the Conservative election campaign, published in The Huddersfield Daily Examiner (Huddersfield, Yorkshire, England) of Wednesday 2^nd December 1992 [No. 42,657, page 15, column 1]:

It is, I fear, too much to expect an admission that their campaign messages were economical with the actualite [sic], but perhaps next time around the electorate may have longer and less-selective memories. I hope so, for our children’s sakes.