Scotland's Minister for External Affairs and International Development, Humza Yousaf has accused the UK government of barring him from visiting Gaza on a fact-finding mission to see the impact of half a million pounds of Scottish Government aid for Palestinians.

Yousaf has written to his Westminster counterpart, foreign secretary Philip Hammond, in protest after the Foreign and Commonwealth Office (FCO) withdrew its support for the trip to the Palestinian territory.

He said that foreign office officials, who had previously been happy to facilitate the trip, made a u-turn after deciding that security could not be guaranteed and that the foreign policy agenda towards Gaza was reserved to Westminster.

A number of UK officials have made the trip in recent months, including Baroness Morris of Bolton, the Prime Minister's Trade Envoy to the Palestinian Territories, and Tobias Ellwood, Parliamentary Under Secretary of State for the FCO with special responsibility for the Middle East and North Africa.

Yousaf however has been unable to secure support for a visit to see first-hand the work being done with £500k of funding that the Scottish Government made to the United Nations Relief and Works Agency (UNRWA) Gaza Flash Appeal in July 2014.

Yousaf's letter to the FCO, shown exclusively to the Sunday Herald, states: "Although FCO officials initially said that they were in principle able to provide support for such a visit, I have since been informed that the FCO view has changed and that the FCO would not support a visit to Gaza for two reasons: firstly that the security situation in the region presents a greater than usual risk and that officials are advising against all ministerial travel; and secondly an assertion that the UK works exclusively to a reserved foreign affairs agenda in Gaza."

It adds: "Given the focus of UK Ministers' visits, I must challenge the proposition that the UK Government works exclusively to a foreign affairs agenda in Gaza: clearly the UK Government is also, and quite rightly, concerned with humanitarian relief and economic development.

"A Scottish Ministerial visit to Gaza would be similarly concerned with humanitarian issues, and would serve to highlight the Scottish Government's international development agenda and the support that it has given in this area.

"I note the FCO offer for the British Consul General in Jerusalem to provide an update on the use of the funding and would welcome this information.

"However, I find it disappointing and frustrating that the FCO is effectively blocking Scottish Ministers from visiting Humanitarian projects in Gaza.

"I would therefore seek your agreement that the FCO will support a visit by a Scottish minister to Gaza once the security situation allows for ministerial travel to Gaza to resume."

Scottish Government funding was supplied to the UNRWA in July last year, following a flare up in the Israel- Gaza conflict during which the Israeli military launched an offensive involving extensive bombardment of the coastal strip.

This action, dubbed Operation Protective Edge by the Israelis, was they claimed aimed at stopping Palestinian rocket fire from Gaza into Israel. More than 2,100 Gazans and 66 Israeli soldiers died and there was widespread damage to civilian infrastructure.

Massive numbers of Palestinians were driven from their homes in Gaza during the fighting, with many seeking safety in UNRWA Designated Emergency Shelters (DES).

In response to the humanitarian crisis, UNRWA expanded its emergency response and launched an appeal for £36 million in addition to the original £40 million set aside.

The fighting came to an end in August with a ceasefire agreement between Israel and Hamas.

Yousaf had previously called for an end to the blockade of Gaza, which the Scottish Government along with other bodies and human rights organisations have described as "collective punishment".

A spokeswoman for the Foreign and Commonwealth Office said: "The safety of British nationals is of paramount importance and the FCO's travel advice for British nationals is clear; we advise against all travel to Gaza."