The Prince of Wales cut a sombre figure as he laid flowers at the permanent memorial in Hyde Park in memory of the 52 people who were killed in the 7/7 attacks. William joined survivors of the London bombings and families of the victims for a moving service at the memorial gardens in Hyde Park this afternoon, to mark the 20th anniversary of the tragedy.

On July 7, 2005, four bombs were detonated on three underground train stations and a double-decker bus during London's morning rush hour, killing 52 people and injuring more than 770. William was one of the last of the 500 guests to take his seat, wearing a dark navy suit and tie for the sad occasion.

The prince had arrived at 15:08, but due to a delay in proceedings, he chatted with Themla Stober, one of the survivors, and Gerald Oppenheim, chairman of the London Bombing Relief Charitable Fund - now the London Emergencies Trust, in the tea tent some 100 yards from the memorial. Families, wearing a mixture of all black and brightly coloured outfits, warmly greeted one another as they started to arrive at the busy London park from 14:30.

Many walked over to the monument, comprised of 52 steel pillars representing each of the victims, to see the names of their loved ones engraved on the memorial, alongside the time of death and the date of death as July 7, 2005.

Floral tributes had been laid on a plaque embedded in the grass near the pillars listing the 52 names alphabetically earlier in the day by the Prime Minister, Mayor of London and official officials.

Families tearfully touched the names on the plaque and paused for a moment of reflection by the wreaths, which were laid at 8:50am to coincide with the moment that the first bomb went off.

The service started 30 minutes late, delayed by long queues at the security gates, and opened with London International Gospel Choir singing Something Inside.

Mr Oppenheim then opened the service, thanking the prince for attending today, adding: "We appreciate all you and members of the Royal Family do for survivors of the 7/7 attacks."

He also thanked the King for his powerful statement released earlier on Monday, and the Duke and Duchess of Edinburgh for attending the service at St Paul's Cathedral in which a minute's silence was observed.

All that could be heard as guests stood for the silence was the sound of the capital's busy traffic and the trees blowing in the wind. Emotional speeches were made by families of the victims as sunshine broke through the grey clouds above.

Jill Foulkes, sister of David Foulkes said that grief never gets easier, but that "the loss and the pain changes" over the years. She recalled the pant in her heart after the birth of her daughter, knowing that she will never meet her uncle.

The parents of Carrie Taylor who died aged 24 at Aldgate station stood with their arms around one another as June told those gathered: "Don't take for granted what you have but treasure every minute."

As her voice cracked, she read the words on her daughter's tombstone: "Missing you is easy we do it every day, loving you is heartache will never go away."

Survivor David Gardener read the names of the killed in the suicide attacks in central London, which saw bombs detonated on three underground train stations and a double-decker bus.

The conclusion of the service was marked by the laying of bright orange flowers on the plaque, with William joining the families in placing the blooms.

After the hour-long service, the Prince joined the survivors and the families of the victims for a private reception at a tea tent some 100 yards from the memorial.