This articles is about the political aftermath of the Carrier Affair.
Vote of No Confidence
On May 9th 1970 Harold Wilson had to admit to the House of Commons that he had known about the complicity of the Minister of Defence with the affair. In the aftermath of the vote where more than half the Labour MPs had voted with the opposition several publicly pronounced their leaving the party and walked out of the house even before the session was over.
"The Great Defection"
Later that afternoon MPs Micheal Sinclair (Llanelli) and Harold St. James (Islington North) publicly resigned both their seats and their party memberships, taking the factions within the party (respectively the centre and right wings) with them for the most part.
Even though this wasn't binding for any individual MPs both at Westminster or in the UK's Senate delegation, when they announced the formation of the "Social Alliance" in the same speech, most of their supporters within the party followed suit over the next few days.
This was aided when the next morning's newspapers also leaked that MI5 had arrested the Minister's secretary because she had been a long-time American spy, and that No.10 had known and suppressed any knowledge of this for several weeks.
Later that year the Alliance merged with the remnants of the Liberal Party and founded the Social Liberal Party.