In 2000, when the Scottish Executive proposed to repeal Section 2A of the Local Government Act, which prevented local authorities from "promoting homosexuality", Souter started the Keep the Clause campaign to oppose their plans, spending £1 million of his own money to organise a private referendum across Scotland.

[8] In 1993, Stagecoach was valued at £134 million and was floated on the London Stock Exchange to access capital for new opportunities for buses and trains overseas.

The company further expanded with the purchase of Citybus, an operator of buses and ferries in Hong Kong, and Coach USA.

[9] Stagecoach then bought a number of the new small bus companies and ran free or low-fare buses to put local rivals out of business.

Stating "it was felt that in the present economic climate it would not be right for any individual to pocket a bonus package of £1.6million", he donated £900,000 to his own charity, the Souter Charitable Trust, which assists humanitarian projects in the UK and overseas.

[14] It was announced in December 2019 that Souter would step down from his role as chairman at the end of the year, but remain on the board as a non-executive director.

[15] Shortly after Souter floated Stagecoach on the London Stock Exchange, he turned his attention to British railways.

Initial experiments consisted of a Scotland to London service branded Stagecoach Rail with carriages attached to the Caledonian Sleeper.

[35] Mana Coach Services and Howick & Eastern Buses were sold to Transdev Australasia in October and November 2019 respectively.

[41] In 2000, the Scottish Executive proposed the abolition of Section 28 laws, which forbade local authorities from "intentionally promoting homosexuality".

"[42] 3,970,712 ballot papers were posted out and 31.8% valid votes were returned, a turnout rate lower than any Scottish national election.

[42] Souter pointed out that the number of people who voted to keep the clause exceeded the number of votes cast for any single political party in Scotland at any election over the preceding ten years,[citation needed] although Scottish voters usually choose from four main parties, not two options.

The society refused the request as it believed the poll "would not be a legitimate democratic exercise to ask people to give an opinion on the repeal of Section 28 without knowing the detail of what would replace it".

Mainstream politicians, including the Scottish National Party (which Souter has supported) largely ignored his poll and disputed whether the result was a true reflection of public opinion, with the Scottish Executive stating that the public had been fed a diet of "misinformation and lies" by Souter's campaign group.

Tatchell said that Souter's campaign was "hateful" and that it is clear that he was using his vast fortune to try to keep a cruel and "bigoted law" intact.

[48] In February 2011 Souter again pledged financial support for the SNP, promising to match every pound they raised with a donation of up to £500,000.

[52] Since Nicola Sturgeon became SNP leader in November 2014, Souter has made no further donation, but in December 2014 he gave £3,500 to the Lewes branch of the Liberal Democrats.

[55] Patrick Harvie, the Minister for Zero Carbon Buildings, Active Travel and Tenants’ Rights stated "what has to be really, really clear is that not just my party, but the Scottish Government, does not share the values of Brian Souter.".

[68] On 18 April 2012 he was inducted into the British Travel and Hospitality Industry Hall of Fame, the first public transport entrepreneur to receive the honour.

In a public statement, Jamieson said: "The First Minister and his party must look seriously at the relationship they have developed with wealthy individuals handing them large sums of cash.

"[72] Salmond denied any wrongdoing in the matter and referred himself for investigation after calls for a probe by Scottish MP Jim Sheridan.

[74] In 1998, Souter described English Northerners (who make up a considerable proportion of his customers) as "the beer-drinking, chip-eating, council house-dwelling, old Labour-voting masses.