The Queen has said her “thoughts and prayers” are with those in Tonga who have been affected by a huge volcanic eruption.

In a message to the nation’s monarch Tupou VI, the Queen said she was “shocked and saddened” by the eruption and shared her sympathies with those who have been cut off from family members.

The Royal Navy will join the international relief effort, sending offshore patrol vessel HMS Spey, which will sail from Tahiti to Tonga carrying water and medical equipment.

Saturday’s eruption and tsunami has badly affected communication services between Tonga and the rest of the world.

Most people have not been able to use the internet or make phone calls abroad, though some local phone networks are still working.

The 95-year-old monarch said: “I am shocked and saddened by the impact of the volcanic eruption and tsunami in Tonga.

“My thoughts and prayers are with the people of Tonga, as you work together to recover from the damage caused.

“It must be incredibly difficult for those who are unable to contact friends and family while communications are disrupted, and I hope that they will soon be restored.”

UN humanitarian officials report that about 84,000 people – more than 80% of Tonga’s population – have been affected by the volcano’s eruption.

New Zealand and Australia have each sent military transport planes carrying water containers, kits for temporary shelters, generators, hygiene supplies and communications equipment.

Deliveries were dropped off without the military personnel coming in contact with people at the airport in Tonga to ensure foreigners do not spread coronavirus.

And the Ministry of Defence said: “Royal Navy ship HMS Spey is sailing for Tonga to offer help with the relief effort after a destructive volcanic eruption and tsunami.

“Defence Secretary Ben Wallace MP authorised the vessel to support the Commonwealth nation with supplies like water and medical equipment.”

Britons Kate Walker, 44, and Joe Caesar, 41, have been the only point of contact to the outside world for the entirety of the country’s population.

The couple, who lived on the island of Vava’u for eight years after moving there in 2012, have passed hundreds of messages on to those fearing for the safety of their friends and family.