The Guardiannewspaper is publishing a compact version today in a move to attract new readers and fend off the growing threat of freesheets.
The Guardian is moving to a smaller "Berliner" format, which is slightly larger than a tabloid and is used by continental European newspapers such as Le Monde.
The shift follows similar downsizing from its rivals the Timesand the Independent, which have both taken readers from the Guardiansince going tabloid.
The Guardian's readership fell to about 358,000 in July, according to the Audit Bureau of Circulation.
Britain's so-called quality newspapers once used their size to set themselves apart from the lurid headlines and topless women of the tabloids. Now only the Telegraphand the Financial Timesremain as broadsheets.
Newspaper executives say that compact papers appeal more to commuters and younger readers, who increasingly get their news from television or the Internet.
"The challenge for us was to remain true to our journalism . . . while at the same time finding a modern print format for a new generation of readers in this country," Guardianeditor Alan Rusbridger said.
"We believe we've found it with the Berliner format, which combines the portability of a tabloid with the sensibility of a broadsheet."
Free newspapers like the Metrohave forced newspapers to innovate, but most national papers have still struggled with steady declines in readership.