The former foreign secretary Jack Straw has thrown his weight behind efforts to persuade the British government to support the Palestinian bid to be admitted to the United Nations as a member state.

Straw, who was foreign secretary from 2001 to 2006 in Tony Blair's government, has written to all 650 members of parliament arguing the case for Palestinian statehood and urging colleagues to stand up and be counted.

The Palestinians are expected to formally submit an application for full membership of the UN – in effect recognition of an independent state – when the world body meets in New York next week. The US has confirmed that it would veto such a bid at the security council.

The UK government is taking a wait and see approach to the question; whether or not the UK backs the Palestinian plan of action will depend on the specific wording of any resolution they put forward.

London recognises that the Palestinian Authority has made significant strides in recent years in reforming itself and reducing corruption. And it acknowledges that a Palestinian state should exist alongside an Israeli state. But Britain believes a meaningful Palestinian state can be the outcome only of a negotiated agreement with Israel. That position sets the UK apart from the nine European states which have already officially recognised the state of Palestine.

Straw's letter tells MPs: "it is vital … that the UK and other European countries have the courage to point the way forward. I believe the way forward is for the international community to recognise a Palestinian state alongside Israel and admit it to the UN."

He urges colleagues to sign an early day motion backing the Palestinian bid and to lobby foreign secretary William Hague on the issue. He says it is a matter of "urgency" to make it clear to the government "how important it is that we, as a country, make the right decision on this".

He reminds MPs that Barack Obama, in his speech to the UN a year ago, looked forward to welcoming "an independent sovereign state of Palestine" as a new member of the world body by September 2011.

He says: "I'm as firm as anyone about Israel's right to security, as a sovereign state. We all understand the fears that Israelis have for their security, but it will not enhance their security to deny the right of self-determination permanently to the Palestinians. The World Bank, the UN, the EU and the IMF have all assessed the progress of the Palestinian Authority and judged it to be ready for statehood."

Recognition at the UN, he says, "is the best way to get peace talks started again".

Catherine Ashton, the EU foreign policy chief, and Blair, the Middle East Quartet envoy, are visiting Jerusalem and Ramallah this week, along with the US envoys David Hale and Dennis Ross, in an attempt to avoid damaging splits at the UN general assembly, which opens next week.

The EU's bloc is divided over the Palestinian bid, and Ashton is anxious for a deal that could unite the 27 nations. Of the so-called big three, Britain and France have not explicitly declared their intentions, and Germany is opposed to full membership. France is inclined to back the Palestinians but is trying to come up with a compromise acceptable to Germany in the interests of EU unity.

A poll released this week showed a majority of respondents in the three countries favoured their governments backing the Palestinian approach to the UN.

A former Foreign Office official said Straw as foreign secretary had taken "a very balanced view" on the Israeli-Palestinian conflict. "But he was never in any doubt that there needed to be a Palestinian state, and at times he was very frustrated by some Israeli actions."

The early day motion, sponsored by Ann Clwyd, calls for recognition of an independent Palestinian state alongside Israel and its admission to the UN. Among its backers are the former Conservative defence minister Nicholas Soames.