Tory former prime minister John Major was one of the first to congratulate Michael Howard on his leadership success - describing him as "the best choice for the party".
Michael Howard: Start of a resurgence in Tory fortunes?
Mr Major, prime minister between 1990 and 1997, said Mr Howard deserved "the support of all present Conservative voters and the millions of
others now so disillusioned with Labour".
Lord Fowler, a former cabinet minister, said: "The atmosphere inside the Conservative Party has changed out of all recognition inside a week.
"I think Michael Howard has been very sensible in the speeches that he made, in saying there is a big mountain to climb.
"I think that the party is more together today than I can remember, not just for six years, but for 10 years."
Michael Mates, the former Northern Ireland minister, said: "He was outstanding,
just what we wanted to hear. Everybody is marching in step and there is a huge
feeling of relief all round."
Charles Kennedy, the Liberal Democrat leader, said: "I do not think his confirmation makes a great deal of difference to the Tory Party, or to British politics.
"It will probably shore up the core Conservative vote, but he may not be able
to extend their appeal beyond that."
Ian McCartney, Labour Party chairman, said: "Michael Howard's selection as Tory
leader today has confirmed the permanent capture of the Conservative Party by
the extreme right.
"Michael Howard will not be able to escape his extremist past. His leadership
will serve as a constant reminder to the British people of his responsibility
for the poll tax, interest rates at 15% and three million unemployed.
"The platform upon which Michael Howard will now fight the Conservative
general election campaign is one of cuts, charges and privatisation."
Dave Prentis, leader of the public services union Unison, warned voters: "Don't be fooled - this is just the same tired old circus with a different ringmaster.
"Michael Howard was part of the last Tory government which left our public
services in tatters, which cut basic state pension, which abolished wages
councils and consigned hundreds of thousands of people to poverty."
John Reid, Health secretary, branded Mr Howard: "Mr Poll Tax, a man associated with one million people
in dole queues".
"The party now has a leader who
represents the unfairness and extremity of the Conservative Party itself."
Theresa May, Tory chairman, said: "I am delighted to pledge my full
support for the leader of the Conservative Party, Michael Howard.
"Michael has successfully united the party behind him and has shown his clear intention to bring all parts of the party together to continue the work of
shaping a party for the 21st Century and ensuring that the Conservative Party is
the credible alternative to this damaging Labour Government.
"I look forward to working with Michael and doing all I can to ensure that this party is ready to win the next general election."
Liam Fox, Mr Howard's campaign chief, said: "I am absolutely delighted. I think it is the beginning of the real resurgence in Conservative fortunes.
"The government might rightly now contemplate the end of their days."
Eleanor Laing, Tory MP, said: "Tony Blair and his immediate colleagues are terrified of a Michael Howard-led party."
Crispin Blunt, the first Tory MP to call for Iain Duncan Smith to go, said: "Michael's unanimous election has unleashed the pent-up forces that were present in the past and ... have now exposed the desire to win and return to power to protect and enhance the achievements of 18 years of Conservative Government, which are
now in the process of being demolished."
Andrew Lansley, former shadow cabinet member, said: "He was received very warmly.
"The party has never been more united in its determination to support him
and to go to success in the next general election."
Anne McIntosh, Tory MP for Vale of York, said: "The key thing is that we are united and determined to win.
"I think there is a real hunger now amongst the parliamentary party for us to proceed and he was given our unanimous support."