Parliament's newest member Rosena Allin-Khan paid an emotional tribute to "passionate campaigner" Jo Cox after winning a Commons seat just hours after the Labour MP's brutal murder.

Dr Allin-Khan dramatically increased Labour's majority in the Tooting seat vacated by Sadiq Khan after his victory in London's mayoral race.

The A&E doctor's win should have taken the number of Labour women in the Commons up to 100.

As the by-election result was announced, Dr Allin-Khan used her acceptance speech to honour Mrs Cox, who was killed in her Batley and Spen constituency on Thursday.

In a sombre statement at Wandsworth Town Hall, she said: "My thoughts and prayers are with Jo's husband and her children. She was a proud and passionate campaigner who will be desperately missed.

"Jo's death reminds us that our democracy is precious but fragile. We must never forget to cherish it.

"Thousands of people voted today and we are all here in recognition of our democratic values."

Turnout in the Tooting contest was 42.5% and Dr Allin-Khan increased Labour's majority to 6,357 over the Conservatives, up from the 2,842 secured by her predecessor in the general election last year.

She took almost 56% of the vote, with the Conservatives on 36%, and the swing from the Tories to Labour was almost 7.3%.

As well as the tragic events on polling day, the by-election has been overshadowed by the European Union referendum contest.

A two-minute silence was observed during the count at Wandsworth Town Hall to allow candidates and officials to reflect on Mrs Cox's murder.

Wandsworth mayor Richard Field said: "This by-election has been tragically overshadowed by yesterday's terrible events and our thoughts, prayers and condolences are with the family and the constituents of Jo Cox.

"We are united with them in grief and we share the loss of a much-loved mother, wife and talented Member of Parliament.

"But even in such tragic circumstances the process of democracy must continue."

Labour MP Tulip Siddiq said: "Congratulations to Rosena for winning Tooting. What an absolute tragedy that she won't be Labour's 100th woman in Parliament. Devastating."