Exactly 100 years ago this week the number of voters in Britain shot up by more than 13 million.

At the previous general election, in 1911, there had been around eight million people eligible to cast a vote.

By the time of the next one there were more than 21 million.

The right to be vote had been extended to almost all men over 21, adding five million voters.

Much more radically, women got to vote for the very first time - bringing in more than eight million more.

At first there were some restrictions. They had be over over the age of 30 and meet certain rules about property ownership. They didn’t get to vote on an even footing with men until 10 years later.

But it was a huge milestone in the growth of democracy, and in the struggle for equality of the sexes. It was the climax of a war that had been going on for the past 50 years.

And this area was an important battle scene. A famous writer was persuaded to change his mind on the issue by what he saw here. He in turn persuaded others to do the same.

Sir Arthur Conan Doyle, author of the Sherlock Holmes novels, was reporting on the war effort and visited what was then a brand new munitions factory near Gretna.

Previously Conan Doyle had been troubled by some of the direct-action, destructive tactics of the suffragettes.

But the sight of thousands of women engaged in the dirty, difficult, physically demanding and highly dangerous task of making cordite for explosives - all doing something that had been thought of as men’s work - had a deep impact on him.

“Hats off to the women of Britain!” he wrote. “Even all the exertions of the militants shall not in future prevent me from being an advocate for their vote, for those who have helped to save the state should be allowed to help to guide it.”

The Devil’s Porridge Museum in Eastriggs, just outside Gretna, has a display running all this month telling the story of the munitions workers and the effect they had on Conan Doyle.

“To me it’s about breaking down the class divide,” argues collections manager Sarah Harper. “A lot of of working class men won the right to vote as well.

“But what Conan Doyle wrote did help women get the vote. He felt they had as much right to have a say in government as anybody else.”

Women may have won the right to vote in 1918 but it took another 97 years for Cumbria to elect a woman to parliament

That happened for the first time at the 2015 general election when Sue Hayman became Labour MP for Workington.

She held the seat at last year’s snap election and is one of 208 women elected that time - a record high. Women now make up 32 per cent of the total of 650 MPs.

Sue praises the reforms to benefit women introduced when her party was in power - increased maternity leave, the introduction of paternity leave, comprehensive childcare, the Equal Pay and Sex Discrimination Acts, Sure Start centres, increases in child benefit and the right to request flexible working.

For her it all started with women getting the vote.

“None of what has been achieved for women over the past 100 years would have happened without the bravery and courage of those women who fought for our right to vote,” she says.

“That’s why it’s so important to celebrate their achievements and the legacy they left for us.

“Achieving the right to vote was a huge stepping stone in the legitimisation of women, not just in the political sphere but also as citizens in their own right.

“But while the centenary is an opportunity for us to recognise how far we have progressed in the fight for gender equality, we must also recognise how much further we have to go.”

The political sphere is one where the room for improvement is obvious. “Parliament must represent the country it serves. Some 51 per cent of the population are women, yet there are twice the numbers of men than women elected in parliament.”

That is precisely the situation in Cumbria. Out of the six MPs who represent the county, four are men and two are women.

And Sue points out: “Since 1918, only 489 women have been elected as members of the House of Commons. At the last election, there were only an additional 12 women elected.

“At the current rate it will take 50 years to achieve gender equality in parliament.

“One hundred years after women first won the right to vote, the fight for political equality continues. This historic deficit needs to be addressed.”

The same applies in local government. Only 32 per cent of the councillors in England are women and progress has been disappointingly slow. “Numbers have increased by less than five per cent in the last 20 years.

“Not only must we get more women to vote, we must also do everything we can to encourage more women to stand for election at both a local and national level.”

What other steps need to come next? The MP wants the laws around sex discrimination to be strengthened, and new policies to tackle the other barriers that still stop women from reaching their full potential.

“Our challenge now must be to build on past achievements and push for full equality and protection for women: financially, in the workplace, in families and homes and in public spaces.”

And she’s optimistic about the prospects. “As we celebrate the suffragettes, we should also look forward to the possibilities for the next 100 years - and make 2018 a year of great achievement for women and girls everywhere.”