* Loss of safe parliamentary seat
* Johnson says 'disappointed'
* Lib Dems hail victory as attack on 'blue wall'
(Adds Johnson's comments, spokesman)
By Alistair Smout and Elizabeth Piper
LONDON, June 18 (Reuters) - British Prime Minister Boris
Johnson suffered an embarrassing defeat in a election on the
outskirts of London on Friday, when his governing Conservative
Party lost a previously safe parliamentary seat to the Liberal
Democrats.
The Conservatives had comfortably held the leafy, affluent
Chesham and Amersham constituency in southern England since its
creation in 1974, capturing more than 50% of the vote on every
occasion. At the last poll in 2019, Conservative Cheryl Gillan,
who died this year, won by a majority of 16,223 votes.
Since a divisive referendum in 2016, Brexit has helped
reshape Britain's political landscape, with people switching
party loyalties in a way not seen for generations. Support for
the Conservatives has surged in northern England.
On Wednesday, Sarah Green, the candidate for the Liberal
Democrats - a centrist, pro-European Union party - won a
majority of 8,028 votes over the Conservative candidate. The
main opposition Labour Party came fourth, with 1.6% of the vote,
its worst showing in decades.
Johnson said it was a "disappointing result", suggesting
there were "particular circumstances" in the area and "it was a
bit bizarre" to suggest his party were on the back foot.
"We are a great one-nation party and we will continue with
our mission to unite and level up because that is the best way
to deliver jobs, prosperity across the whole country," he told
reporters.
But Lib Dem leader Ed Davey said it was a sign of things to
come, with his party ousting the Conservatives from traditional
strongholds in England's affluent south.
"Across the south, the Tory Blue Wall is beginning to
crumble," he said in a statement. "Here and in great swathes of
the country, only the Liberal Democrats can beat the
Conservatives and breach their Blue Wall."
NEW NORTH/SOUTH DIVIDE?
The result may cause some nervousness in the Conservative
Party, which has targeted traditional Labour-supporting voters
in northern England but, according to some of its lawmakers, has
increasingly ignored its strongholds in the south.
Johnson's parliamentary seat is just 10 miles away, in West
London.
While governing parties often lose out at so-called
by-elections, the Lib Dems focused their campaign on local
issues, such as the new High Speed 2 rail link between London
and northern England which cuts through the area.
The Conservatives have also been criticised about changes to
planning laws, which some fear could mean more building of homes
over green fields, something Johnson said was a misunderstanding
as the government wanted construction on brownfield sites.
"I think there's some misunderstanding about the planning
reforms, perhaps even some wilful misunderstanding," he said.
"What we want is sensible plans to allow development on
brownfield sites ... but I do think young people growing up in
this country should have the chance of home ownership."
(Reporting by Alistair Smout, Elizabeth Piper and Michael
Holden
Editing by William Schomberg and Catherine Evans)