Two Palestinians jailed for the 1994 bombing of Balfour House in North Finchley have lost a High Court appeal against their convictions.

There were cries of 'shame' from the public gallery on Thursday as three Appeal Court judges ruled against Samar Alami and Jawad Botmeh. Alami, 33, wearing a white T-shirt with the word 'innocent' scrawled across it in red lettering, looked pale and shaken at the verdict. Botmeh, 31, did not appear in court.

The pair, both British residents of Palestinian origin, were jailed for 20 years in 1996 for their part in car bomb attacks on the Israeli embassy and Balfour House. Twenty people were injured in the explosions, seen at the time as part of a wider campaign to destabilise the Middle East peace process.

Botmeh and Alami have always claimed they were the victim of a miscarriage of justice. They appealed on the grounds of non-disclosure of evidence by the Crown at their original trial and new evidence which had come to light since then.

Supporters had hoped their convictions would be quashed and a retrial ordered. But dismissing their appeal, Lord Justice Rose told a packed court five that the withheld evidence would not have had an impact on the original trial.

"There is, in our judgment, no demonstrated breach of the appellants' Article 6 rights and no reason to regard their convictions as unsafe."

Their solicitor, Gareth Peirce, said her client had not wanted to make the journey from prison in Durham, Northumberland, for two minutes in court. The judges also ruled against a defence application to reduce their 20-year sentence.

"Those who, whatever their motivation, place bombs of this kind in the heart of this city cannot expect their conduct to be treated by anything other than very substantial terms of imprisonment," Lord Justice Rose told the court.

"In our judgement it is not arguable that the 20-year terms given by the judge against these appellants were excessive and accordingly this application in relation to their sentence is refused."

In statements handed out by their supporters, the pair vowed to continue their campaign for freedom. Botmeh said: "Myself and Samar had an unfair trial that was followed, after a long wait, by an unfair appeal. "This was a political trial from day one and we are totally innocent. The real perpetratorsstill remain free. We were only convenient scapegoats.

"A huge amount of evidence is still hidden, all of which points away from us. We will carry on the struggle for our freedom and justice as part of the larger struggle for our people's freedom. I've got to call my parents in the West Bank now and I'm dreading telling them the news."

Alami said: "Today justice has lost, injustice has won, again. The judgment further perverts justice, the judges seem to have blindness in their hearts and minds.

"I will never regret being part of the Palestinian people's struggle for justice and basic rights, for life with a minimum of dignity, humanity and freedom."

Outside court Samia Botmeh, Jawad's sister, told the Times Group: "This wasn't entirely unexpected, but we hoped for something positive. Okay, dismiss the appeal but at least shorten their sentences, just do something because it is obvious there is so much evidence which throws doubt on the case."

Randa Alami, Samar's sister, said the campaign for justice would continue.