Lib Dems' Baroness Nicholson rejoins Conservatives
Baroness Nicholson of Winterbourne has returned to the Conservative Party 21 years after she defected to the Liberal Democrats.
The peer said she would rejoin the party next week "with tremendous pleasure".
She said her energies were "dedicated to fighting for our new PM and her policies".
A former Tory party vice-chair during Margaret Thatcher's government in the 1980s, she left the party in 1995.
At the time, Lib Dem leader Paddy Ashdown described her move as a "historic, principled decision".
He later said she was a believer in "one nation. In values of decency and fairness. In the politics of conscience and compassion as well as enterprise and initiative."
Baroness Nicholson resigned the Lib Dem whip during parliamentary recess this summer.
'Fighting for Britain'
Previously MP for Torridge and West Devon for a decade until 1997, she served as an MEP from 1999 to 2009, and has been a peer since 1997.
Announcing her decision on Saturday to rejoin the Tories, she said: "My greatest strengths are the Conservative strengths and I will be fighting for Britain from the Conservative benches from now on in."
Listing her reasons for rejoining the Tories, she highlighted Theresa May's education speech on Friday as evidence that the prime minister "leads a party with a real commitment to delivering for the next generation and building a country that works for everyone".
Mrs May said all schools in England are to be given the right to apply to select pupils by ability, under plans also allowing grammar schools to expand.