In 1998, Mackintosh celebrated thirty years in show business with Hey, Mr. Producer!, a gala concert featuring songs from shows he had produced during his career. The concert was performed twice, on 7 and 8 June, with proceeds going to the Royal National Institute of Blind People and the Combined Theatrical Charities. Many celebrities took part, and the 8 June performance was attended by Queen Elizabeth and Prince Philip, Duke of Edinburgh.
In 1998 Mackintosh was named in a list of the biggest private financial donors to the Labour Party, a decision he later claimed to regret, saying: "Labour really f****d it up. They were profligate at a time when we were doing well. That's why we have the problems we have now. They didn't save any money for a rainy day. It couldn't have been worse these last 12 years." In the 2015 British general election, Mackintosh donated £25,000 to the successful Conservative candidate for Somerton and Frome, David Warburton. In the 2016 EU Referendum, Mackintosh voted for the UK to leave the EU, stating that it was "not because I don't love Europe - I do huge amount of work in Europe and love Europeans - but there is something wrong with a system where the Fat Controller is not accountable".