To Denis Healey's advice that "if you're in a hole, stop digging", Israel's Prime Minister, Ariel Sharon, might reasonably reply: "It's my only option." In personal terms, he will surely be relieved by the Israeli Supreme Court's decision yesterday to uphold the lower court's ruling that he shouldn't be indicted on corruption charges. But in political terms, his situation goes from bad to worse.

To Denis Healey's advice that "if you're in a hole, stop digging", Israel's Prime Minister, Ariel Sharon, might reasonably reply: "It's my only option." In personal terms, he will surely be relieved by the Israeli Supreme Court's decision yesterday to uphold the lower court's ruling that he shouldn't be indicted on corruption charges. But in political terms, his situation goes from bad to worse.

Still sore from Mr Sharon's determination to press ahead with his plan for withdrawal from Gaza, despite the vote against by his own Likud Party, the party's central committee this week also firmly rejected his efforts to form a broader governing coalition with the Labour Party.

Mr Sharon says that he is still intent on proceeding with unilateral disengagement from Gaza and with talks with the Labour Party. But there is an air of increasing desperation about his manoeuvring. Without the backing of his own party, and with the support of the main opposition party only as far as the Gaza part of his strategy is concerned, it is difficult to see how he can go on.

Even the backing of Washington cannot be guaranteed now that the Israeli Prime Minister, in an effort to bring Likud on side, has agreed to a substantial increase in settlement activity on the West Bank in direct contradiction to the US-led road map to peace. Until the US election, the contenders for the presidency will say nothing that can be held against them by Israel's supporters in America. But whoever wins the election in November is bound to push again for Israel to abide by the peace plan.

Early elections may now be inevitable in Israel. But even these are unlikely to solve the embattled Prime Minister's problems. Public opinion is in favour of a Gaza pull-out, but no longer has much faith that the Prime Minister has the answer to the problems of peace and security. Mr Sharon is too shrewd a tactician to be written off yet. But, as the Palestinian leader, Yasser Arafat, struggles with similar problems of falling support within his party, there is a growing sense that the sooner these two old and discredited warhorses leave the field the better.