Buoyed by the British Labour Party election gains this week, Vermont Senator Bernie Sanders on Saturday urged a summit of progressive activists who propelled his presidential candidacy to ramp up efforts to win elections and help remake a Democratic Party he deemed a failure.

"They won those seats by standing up to the ruling class," he said, referring to the British elections and citing wins by progressive US candidates in several state and local races while writing off losses as evidence liberal progressives could still be competitive even in conservative states.

But Mr Sanders, who lost the Democratic nomination nearly a year ago to Hillary Clinton, showed little interest in a push by "Draft Bernie" activists who want him to start his own "People's Party." Many activists blame establishment Democrats for losing to President Donald Trump by failing to embrace a more populist left-leaning agenda.

Sanders headlined the three-day "People's Summit" in Chicago, attended by celebrity activists including actors Danny Glover and John Cusack, which brought together main progressive groups such as National Nurses United, Democratic Socialists of America and People for Bernie.

Many activists said they hoped to transform the momentum from recent protests such as January's Women's March in Washington into concrete plans to support a growing wave of grassroots candidates to secure electoral power.

"We could have 10,000 people marching, but if we don't have some means of translating that into winning political office and enacting a legislative progressive agenda, at the end of the day, what does it amount to?" said Nick Brana, the former staffer for the Sanders campaign leading the "Draft Bernie" group.

General Election 2017: Big beasts who lost their seats Show all 7 1 /7 General Election 2017: Big beasts who lost their seats General Election 2017: Big beasts who lost their seats Nick Clegg Picture By Darren O'Brien/Guzelian Picture Shows Former MP, Nick Clegg delivers a speech despite losing the Sheffield Hallam Seat. Labour candidate, Jared O'Mara (Front), defeats Nick Clegg to take the Sheffield Hallam seat. picture taken 08/06/2017 Darren O'Brien General Election 2017: Big beasts who lost their seats Gavin Barwell LONDON, ENGLAND - OCTOBER 07: Gavin Barwell MP arrives at Number 10 Downing Street on October 7, 2013 in London, England. British Prime Minister David Cameron announced a Government reshuffle today. (Photo by Oli Scarff/Getty Images) Getty General Election 2017: Big beasts who lost their seats Angus Robertson General Election 2017: Big beasts who lost their seats Nicola Blackwood PA General Election 2017: Big beasts who lost their seats Alex Salmond PA General Election 2017: Big beasts who lost their seats Rob Wilson Mandatory Credit: Photo by Geoffrey Swaine/REX (1096138i) Rob Wilson, Conservative MP for Reading Funeral of Murdered Student Asha Muneer at Rivermead Leisure Centre, Reading, Britain - 28 Jan 2010 Rex Features General Election 2017: Big beasts who lost their seats Ben Gummer Minister for the Cabinet Office Ben Gummer arriving at 10 Downing Street, London for the weekly cabinet meeting. PA

With Trump mired in controversy over incidents such as the firing of former FBI Director James Comey, and Democrats having lost ground in statehouses and in Congress, RoseAnn Demoro, head of the nurses union, said the movement Mr Sanders began was at a "tipping point" of broadening its support.

Leaders with the Democratic Socialists of America said their membership has bloomed from 6,000 before the election to 22,000.

"We're closer but we're not yet winning," said activist and writer Naomi Klein.

Still, Mr Sanders credited progressives with increasing public acceptance of proposals such as a $15 (£12) minimum wage, renegotiating trade policies and offering free college tuition. He got a standing ovation when he said the California Senate recently passed a single-payer health care plan.