Holocaust survivors have gathered in central London to light candles and remember the victims of genocide on Holocaust Memorial Day.

A group of nearly 30 survivors and their families stood on the steps of Piccadilly Circus holding flickering candles to remember the six million Jews murdered during the Holocaust, as well as the millions from other groups killed under Nazi persecution.

The day is also used to remember the millions killed in subsequent genocides in Cambodia, Rwanda, Bosnia and Darfur.

The group looked up at the landmark junction’s giant billboard, where portraits of them and fellow survivors were displayed.

A film was also screened showing people, including political and religious leaders, lighting candles to mark the day.

One of the photographs, taken by the Duchess of Cambridge, showed survivor Steven Frank.

Born in the Netherlands, Mr Frank was one of only 93 children who survived the Theresienstadt ghetto camp out of the 15,000 children who were sent there.

His father, an eminent lawyer, was active in the Dutch resistance when the country was under Nazi occupation.

Mr Frank, now in his late 80s, told the PA news agency: “And then one day he went to the office to go to work, and he’d been betrayed, and he was taken away.

“So he ended up in prison, where we know he was tortured, badly beaten, from where he was taken to Westerbork, and from Westerbork to Auschwitz, where he was murdered in the gas chambers on January 21 1943.

“So very, very close to Holocaust Memorial Day, which is so very, very special for me.”

The portrait of Mr Frank showed him with a tin pot, in tribute to his mother who, while working in Theresienstadt, collected crumbs that she made into a paste to feed to her children.

Olivia Marks-Woldman, chief executive of the Holocaust Memorial Day Trust, wiped tears from her eyes as she spoke of the event’s significance.

She said: “Holocaust Memorial Day is such an important day for everybody in the country to come together and we’re doing so at a time when the world can feel quite fragile and we can quit feel quite vulnerable to division and hostility.

“We only saw yesterday an antisemitic attack with two people being assaulted.

“And that can leave people feeling particularly vulnerable, so to be able to come into the heart of London, into Piccadilly Circus and see photographs of Holocaust survivors in enormous displays, and to be able to celebrate the lives they have rebuilt in Britain just feels a very profound moment.”

Holocaust Memorial Day takes place each year on January 27, which marks the anniversary of the liberation of the Auschwitz-Birkenau concentration camp, the largest Nazi death camp, in 1945.

National landmarks lit up in purple, including the London Eye, the Houses of Parliament, the Natural History Museum and Cardiff Castle.

Households across the UK joined the commemorations by lighting a candle in their window at 8pm.

A candle was also burning in the window of the Prime Minister’s residence 10 Downing Street.

Laura Marks, chair of the Holocaust Memorial Day Trust, spoke of the meaning of this year’s theme, “One Day”.

She said: “One day is Holocaust Memorial Day, one day Bergen-Belsen was liberated.

One day in the future maybe we won't need Holocaust Memorial Day because we'll have learned to tolerate each other

“One day each of our survivors got out or their parents were taken away.

“One day in the future maybe we won’t need Holocaust Memorial Day because we’ll have learned to tolerate each other, we’ll have learned to respect difference, to celebrate difference.”

She added: “There’s obviously a huge sadness but it’s also a hope and that light in the darkness, and I choose to focus on that and think about how together with the candles we can actually change the world we’re living in and really light the darkness.”

During a special ceremony in Westminster to mark Holocaust Memorial Day, Commons Speaker Sir Lindsay Hoyle urged people to call out intolerance and work together to build a “happier future”.

Ms Marks, Commons Leader Jacob Rees-Mogg, shadow minister David Lammy and Rabbi Debbie Young-Somers were among those taking part in the ceremony.

Sir Lindsay said in his opening address: “The Holocaust threatened the very fabric of civilisation, and genocide must be still resisted every day.

“Our world often feels… vulnerable, and we cannot be complacent. Here in the UK, as elsewhere, prejudice and the language of hatred must be challenged by us all.”

Closing the ceremony, he added: “I hope it has given us all pause for thought to consider how we might call out, counter messages of hate, intolerance, and instead work together to create a better, safer, and a happier future.”

Speaking to the PA news agency after the event, the Commons Speaker said: “This event was absolutely important to me. Holocaust (Memorial) Day, and remembering, bringing the House together, whether it’s staff (that) work for the House, whether it’s MPs, peers, journalists, we all came as one. And that… was so important. We stood shoulder to shoulder.

“We are calling out hatred, racism, intolerance, because we believe that we shouldn’t forget six million lives that were persecuted, taken away by the Nazis, right through to Darfur.”