Carey Oppenheim has had a working relationship in one form or another with Lisa Harker for years, including writing a book with her. In the summer, they were appointed co-directors at the London-based Institute for Public Policy Research (IPPR), the progressive think tank they have worked for in the past.
Together they are among the most senior jobsharers in the country, and two of the most influential women in British politics. Their co-directorship is a sign that attitudes are changing.
"There's a strong view generally that leadership is about a single person but we're trying to show that there can be different models of leadership," Oppenheim says. "People at the IPPR have been very adaptable to the fact the person in our office may be either me or Lisa."
Oppenheim chose to jobshare because she wanted to spend more time with her two teenage daughters. For Harker, the decision came after an accident that took a long time to recover from.
"I realized during this time that I wanted more time to spend doing other things I liked and have the space to do a variety of things, both unpaid and paid," she said. "I wanted to pursue hobbies, see friends and family and to reflect on my work generally."
Both women had applied to other positions as a partnership, and found reactions varied.
"I think people were quite wary," Oppenheim says. "They felt they would be taking a double risk and they couldn't understand why we couldn't just be director and deputy director."
The two women each work three days a week with one day of crossover and say that if one leaves the job, the other will as well.
"We're a package," Oppenheim says.
So far their staff have reacted extremely well.
"Not only do we get two brains instead of one, but I think it's great that we're setting the example of how flexible working can work to the benefit of everyone in the world of policy and politics," said Sonia Sodha, a research fellow at the IPPR.
As with Oppenheim and Harker, Samia al Qadhi and Christine Fogg work three days a week as joint chief executives of the UK charity Breast Cancer Care and are similarly enthusiastic about shared leadership.
Not only do you get "double the intellectual" input at the top of an organization, al Qadhi said, but it adds rigor to decisions as they are discussed with someone who has an "equal commitment."
"What's more," she said, "it massively reduces stress, pressure and isolation because you have somebody you trust and whom you talk through worries and anxieties with."
While there are many examples of women who jobshare, few do so in senior positions. For men, jobshare arrangements are rare at all levels. But there are those who buck convention.
Simon Toseland shares his post in communications with a female colleague at Sustrans, a sustainable transport charity. He says that arrangements such as his are undervalued.
"If you get the right people, then the sum of two people working together can be more than one person working on their own as you have more energy and more enthusiasm and different people bring different approaches to the work," Toseland said.
Two days a week, Adam Coffman looks after his children. The other three days he jobshares with a woman as a senior development officer for CTC, a UK cyclists' organization. Though he has worked part-time before, this is his first official share.