Renewed violence in Gaza will "not shake the resolve" of the UK's major aid agencies delivering humanitarian relief in the war-torn region, t he Disasters Emergency Committee (DEC) has said.
The DEC, which brings together 13 leading UK aid charities in "times of crisis", said it was "saddened" by the latest outbreak of violence following the end of a ceasefire between Israel and Palestine.
Israel said it had resumed air strikes in the Gaza Strip after Palestinian militants Hamas fired 18 rockets following the end of a three-day truce this morning.
The DEC admitted some agencies may be forced to temporarily suspend their aid effort but they would seek to resume operations "at the first opportunity".
A DEC spokesman said: "We are saddened by this renewed violence but it will not shake the resolve of our members and their partners in Gaza to continue to find ways to provide whatever help they can.
"DEC agencies have for the last month constantly sought opportunities to provide life-saving relief whenever and wherever the circumstances allowed. Even those agencies that might now be forced to temporarily suspend work by the latest outbreak of violence will immediately seek to resume operations at the first opportunity.
"The help of the UK public in supporting the DEC Gaza Crisis Appeal remains an essential support for aid workers risking their lives to help others in Gaza."
The DEC said agencies used the temporary truce to supply clean water, food, household items, emergency shelter and medical supplies, as well as help children and other vulnerable people to cope with the psychological effects of the conflict.
The rapid scale-up of the aid effort came as the DEC launched its Gaza Crisis Appeal including a televised advert which all of the UK's main broadcasters have agreed to show.
The latest ceasefire between Israel and Hamas was the longest lull in a war that has killed nearly 1,900 Palestinians so far, 75% of them civilians, according to the United Nations. Israel has lost 67 people, including three civilians.
The DEC said that the conflict has led to the entire population of Gaza being left without adequate access to medical care and around 1.4 million people with none or very limited access to water and sanitation.
Hundreds of thousands of people have been forced to flee their homes over the past month and 65,000 people have seen them destroyed or damaged beyond repair.
Some agencies have worked through the fighting despite the considerable risks involved and others have responded when and where lulls in the fighting allow, the DEC said.
Ted Tuthill, disaster recovery operations manager at the British Red Cross said: "Many agencies working there are used to working in these conditions. In the last four weeks, when the escalation of violence has been much more intense, they have still delivered aid on the ground.
"This won't shake our resolve. Ultimately we want a ceasefire as soon as possible."
Former Liberal Democrat leader Sir Menzies Campbell said: "It is profoundly disappointing that the temporary truce has now broken down, but it does not absolve both Hamas and Israel of their obligations to conduct themselves in accordance with international law.
"Israel is unquestionably entitled to defend itself against indiscriminate rocket attacks but the same principles of law which allow it to do so impose an obligation of not acting in a disproportionate manner.
"The wreckage of Gaza in so many places does not amount to a proportionate response to the danger that Israeli citizens are exposed to."
So far Oxfam has delivered safe water to up to 175,000 people per day and the British Red Cross partners are supporting emergency medical services.
Donations are already being received: £25 can buy 150 bandages, £50 can feed five families for a day and £100 can provide an emergency shelter kit and blankets for one family.
In 2009 the BBC and Sky News refused to broadcast the DEC's appeal to tackle the humanitarian crisis in Gaza, claiming it would compromise their impartiality in reporting the conflict.
But both networks as well as ITV, Channel 4 and Channel 5, which broadcast the 2009 appeal, have accepted the latest film meets the DEC's "appeal criteria", and will screen it today.
The Government has said it will match the first £2 million of donations from members of the public to the DEC's appeal.
International Development Secretary Justine Greening said: "Four weeks of violence have left people in Gaza in desperate need of food, shelter and medical supplies. The British people have shown immense generosity in situations like this and the UK Government will help that generosity go twice as far.
"For people wanting to help civilians in Gaza caught up in this crisis, giving now means every pound they donate will buy twice as many food parcels, provide twice as many blankets and help twice as many people to get through this crisis."
The new £2 million commitment will take the UK Government's total support for the people of Gaza since the start of the crisis to £17 million.
To make a donation to the DEC Gaza Crisis Appeal, visit www.dec.org.uk, call the 24-hour hotline on 0370 60 60 900, donate over the counter at any high street bank or post office, or send a cheque. Donations of £5 can also be made by texting the word SUPPORT to 70000.
Reacting to the expiry of the ceasefire, Labour MP Richard Burden said efforts should be redoubled for the truce to be reinstated.
The chairman of the All Party Parliamentary Group on Britain-Palestine went on: "The expiry of the latest ceasefire means that civilians will once again be those who will suffer most.
"Those in Israel will again take to shelters from rockets and those in Gaza will again have nowhere to go which is safe from missiles and shells.
"Everyone must redouble efforts for the truce to be reinstated and all the feedback from Gaza, not only from Hamas, is that the blockade has to be lifted.
"Ceasefire can't be a cover for Gaza remaining a prison for 1.8 million people, with the world again looking the other way as Israel throws away the key.
"In the meantime what we can all do is support the DEC appeal to get the humanitarian aid in that people in Gaza so desperately need."