On a steamy night at the Labour Party conference, I met Nick Partridge of the Terrence Higgins Trust coming out of the Health Hotel drinks reception.
"It's like the Black Hole of Calcutta in there," he said, so we sat in the breezy bar of the Old Ship and exchanged greetings as political friends passed in and out. Colleagues came to drag us in, but stayed to join the conversation as we caught up with the changes that had taken place in each other's organisations in the past couple of years.
There were so many points in common that we agreed to continue the conversation round the table - unlike so many resolutions, we meant this one. So a few months later, eight of us sat down to dinner and talked, making one discovery after another about the similarity of priorities between two apparently very different charities. Here are a few: concern that HIV/Aids and cancer are falling off the government agenda; the radical NHS changes and financial pressures that may be a threat, an opportunity or both; balancing concern for the dying with the needs of the living; telling a truthful and consistent story through a media baying for the sensational; developing the role of service users in research; extending our bandwidth from healthcare to social care; and growing our fundraising in line with the needs of our beneficiaries.
The evening has already made us at Macmillan think about different models, departing from our well-worn conventions for new ones where we have the reassurance that another charity has successfully challenged and taken risks. We think of the Terrence Higgins Trust, admiring its metamorphosis through mergers and population changes, and its migration to a broader focus on sexual health.
Why did this work? Finding a date for eight busy people needs long notice.
Similar structures are important, too; the two bodies each have senior staff heading policy, communications and services. Although different in size, both are large and well established, so we were on level ground.
A relaxed dinner was a great help, but the key was the openness with which our colleagues approached each other, with a genuine interest and excitement to learn and compare.
It was a productive and cost-effective developmental experience, and we have already extended our contacts. We shall meet the trust again, but we are also thinking of other organisations with which we could share similar, mutual learning events.