Londoners have expressed their pride at living in a "strong, tolerant, progressive and diverse" city the day after the Westminster terror attack.

Social media users are posting messages of solidarity and defiance under the hashtag #WeAreNotAfraid, with some challenging the right-wing response to the incident.

Four people died and 29 were treated in hospital for injuries when a man drove a car along a pavement and stabbed a policeman outside Parliament before being shot by officers.

The people hospitalised after the attack were from 11 different countries, confirmed Theresa May.

Among the injured were: 12 Britons, 4 South Koreans, 3 French, 2 Romanians, 2 Greeks, 1 German, 1 Pole, 1 Irish, 1 Chinese, 1 Italian and 1 American, she said.

Seven people remain in a critical condition in hospital after the attack, which police are treating as a terrorist incident.

Nigel Farage blamed the attack on political support for multiculturalism, claiming it had created a “fifth column” of terror supporters within Western societies.

The former Ukip leader challenged the assertions of the Prime Minister and Mr Khan that Britain stands united in the face of attack, insisting that the people in fact want “answers” about what they are going to do.

"Hopkins, Farage, anyone using the Westminster attack to further a venomous political agenda doesn't represent us," wrote Twitter user Nicole Smith.

Another user, Zoe Paramour, wrote: “London is strong, tolerant, progressive and diverse – we are not afraid.”

Terri Paddock said: “Dear Americans and Trump fans. Pray for London if you want but don’t use us to justify racism and religious hatred.”

London's mayor Sadiq Khan told the BBC terrorists may want to target cities like London because its citizens “respect, embrace and celebrate” one another.

“As the Mayor of London, I bring many experiences to this job including the faith I belong to and the experiences I’ve had growing up in the greatest city in the world,” he said.

Westminster falls silent in memory of terror attack victims

The four victims included the wounded officer, named as 48-year-old Keith Palmer, and the assailant who was shot dead by police.

Spanish teacher Aysha Frade, 43, and a 30-year-old man were also killed in the attack.

Brendan Cox urged Britain not to let itself be divided by the incident, saying the assailant no more represents British Muslims than his wife’s murderer represented the people of Yorkshire.

“What the terrorist would like to happen is for us to fall apart and start blaming groups of people, to say that in some way this is Muslim or Islam as a whole,” he told Radio 4's Today programme.

However, some far-right commentators cited London’s cultural diversity as a reason for the attack.

Paul Joseph Watson, a writer for right-wing website Infowars, said: “London is probably the most ‘diverse’ city in the world and look what happened. Is diversity still our strength?” in a tweet.

Mr Farage told Fox News the attack bolstered US president Donald Trump's case for tougher vetting of migrants from some Muslim nations, claiming that countries which open their door to immigration from the Middle East are “inviting in terrorism”.

“The idea that this whole country is united, which is what we are hearing from our leaders, I'm not sure is true,” he said.

“I think the British people want some answers from our leaders as to what they are now going to do.”

In pictures: Westminster attack Show all 9 1 /9 In pictures: Westminster attack In pictures: Westminster attack An air ambulance lands after gunfire sounds were heard close to the Palace of Westminster in London PA wire In pictures: Westminster attack MPs wait until the situation is under control in Westminster. 'The alleged assailant was shot by armed police,' David Lidington, leader of the House of Commons, told the house. BBC News In pictures: Westminster attack Crowds gather in Westminster after shooting incident, which police are treating as terror attack BBC News In pictures: Westminster attack Police were also called to an incident on Westminster Bridge nearby AP In pictures: Westminster attack Early reports indicate the car, which mounted the pavement on Westminster Bridge and mowed into around a dozen people, was the same vehicle which then rammed into the railings of the Palace of Westminster, just around the corner Reuters In pictures: Westminster attack Security sources described the suspected assailant as a middle-aged Asian man, who is understood to have left the car before attacking a police officer with a seven-to-eight inch knife PA wire In pictures: Westminster attack Police have asked people to avoid the immediate area to allow emergency services to deal with the ongoing incident AP In pictures: Westminster attack One woman has died and a number of others, including the police officer, have been hurt, according to a junior doctor at St Thomas' Hospital Reuters In pictures: Westminster attack At least three gun shots were heard by those inside Westminster, and proceedings in the House of Commons have been suspended AP

“We've made some terrible mistakes in this country, and it really started with the election of Tony Blair back in 1997, who said he wanted to build a multicultural Britain,” he added.

“I do actually think that the moment has come for us to actually point the blame. What these politicians have done in the space of just 15 years may well affect the way we live in this country over the next 100 years.”

Donald Trump Jnr also stoked controversy after he criticised Mr Khan on Twitter, sharing a link to a six-month-old story by The Independent that quoted the mayor saying terror attacks were “part and parcel” of living in a global city.

“You have to be kidding me?!” wrote the US President’s eldest child.

When asked about the criticism, Mr Khan sharply said: “I’m not going to respond to tweets by Donald Trump,” likely referring to Trump Jr.

Responding to news of the attacks, mayor of Paris Anne Hidalgo said both London and Paris are “tolerant, cosmopolitan cities, open to the world, that draw their strength from their diversity”, reported The Telegraph.