David Cameron has come under renewed pressure over his policy on Gaza with a call from MPs to do more to persuade Israel to lift unjustified restrictions on the movements of Palestinians.
The Commons International Development Committee said some controls on the movements of Gazans - who are rarely allowed to leave the territory - were not "proportionate" and in some cases ran counter to international law.
It urged the Government to do what it could to persuade the Israelis to improve the supply of water and electricity which are frequently cut off.
The call came after Foreign Office Minister Baroness Warsi announced she was quitting the Government as its policy on Gaza was "morally indefensible" and counter to Britain's national interest.
The committee - whose members visited Israel and the Occupied Palestinian Territories earlier this year - said they were "shocked" by what they had seen.
While they appreciated Israel's security concerns in the face of Hamas rocket attacks, they warned that its policies were ultimately likely to prove counter-productive.
"We saw a country whose people have known immense suffering now imposing conditions on their Palestinian neighbours which cause a different but very real suffering and often without real security justification," the committee said.
"We saw Israel taking a range of actions that hinder Palestinian economic development and must, at the very least, cause deep resentment on the Palestinian side, even amongst the most moderate and pragmatic people, and so will actually worsen Israel's own security."
The committee also questioned evidence provided to it by the Israeli Embassy in London following their visit.
"Some of the evidence we were given on our visit are difficult to reconcile with that subsequently provided by the Israeli Embassy," it said.
A Government spokesman said: "We welcome the International Development Committee's strong support for our work on economic development in the Occupied Palestinian Territories and agree that sustainable development can only happen if economic restrictions are eased.
"We will continue our work to help strengthen Palestinian institutions and build a prosperous and stable future Palestinian state. We are also committed to lasting change in Gaza, though we recognise that reconstruction and growth cannot happen until we have a durable ceasefire."