Its alumni include Sir Walter Scott and Robert Louis Stevenson and the mysterious debating society's format has been unchanged since the Enlightenment, but the bastion of male-only privilege was said to be behind the times for refusing to admit women.

Now the Speculative Society, based in Edinburgh University's Old College, is to allow female member for the first time but only after a last gasp effort by a section of the club.

A three to one in favour vote decided the historic society's future.

A society spokesman said: "Speculative Society is delighted to announce its intention to admit female members.

"The society has actively discussed female membership for many years and a consultation of our membership was concluded in February with members voting three to one in favour of admitting women.

"We have welcomed female candidates for membership since then and expect to admit female members in the next session which begins in

October.

"We hope that our newly established position on female membership will strengthen the society and enable us to continue our 250-year-old

tradition of advancing public speaking and literary composition long into the future."

An Edinburgh University review, by vice-principal Professor Mary Bownes, called for an overhaul of rules and followed criticism over the men-only policy at the "Spec".

Plans for a £35 million refurbishment of the Old College which houses the society's historic rooms have also been announced.

The Speculative Society said it is an independent debating society which was founded in 1764 "for the purpose of improvement in literary composition and public speaking."

It is one of the oldest debating societies in the world.

Many of its members have risen to prominence in public life, including Sir Walter Scott and Robert Louis Stevenson.

While there is currently a handful of student members, the Ordinary Membership - those in the first three years of their membership and attending weekly - mainly consists of young people who are at the start of their careers and who enjoy debating and reading essays and improving their

public speaking and debating skills.

The Extraordinary Membership consists of those who have been a member for longer than three years.

They are no longer required to attend weekly but may attend from time to time.

The original eighteenth century rooms of the Speculative Society were demolished to make way for the Old College of the University of Edinburgh.

In return for making their site available, the university provided the society with replacement rooms, designed by William Henry Playfair.

The society remains in the rooms built for it in 1819, which are now A listed.

The Speculative Society celebrated its two hundred and fiftieth anniversary in 2014 with a number of events, including a public lecture about the Society given by Professor David Purdie at the Scottish National Gallery.

The format of the society and its weekly meetings has remained mostly unchanged since the Enlightenment. At each meeting, a member presents an essay, on any subject, for constructive criticism, and a formal debate is held.

Vice-Principal Mary Bownes said: "We welcome the Speculative Society's admission of women to membership. This is a positive change in keeping with the University's commitment to equality and diversity."