Règle correspondante
United Kingdom of Great Britain and Northern Ireland
Practice Relating to Rule 55. Access for Humanitarian Relief to Civilians in Need
Section B. Impediment of humanitarian relief
The UK Military Manual (1958) provides:
The Occupant must not in any way whatsoever divert relief consignments from their intended purpose except in cases of urgent necessity and then only in the interest of the population of the occupied territory as a whole and with the consent of the Protecting Power … The Occupant must facilitate the rapid distribution of these consignments. 
United Kingdom, The Law of War on Land being Part III of the Manual of Military Law, The War Office, HMSO, 1958, § 541.
Under the UK ICC Act (2001), it is a punishable offence to commit a war crime as defined in Article 8(2)(b)(xxv) of the 1998 ICC Statute. 
United Kingdom, ICC Act, 2001, Sections 50(1) and 51(1) (England and Wales) and Section 58(1) (Northern Ireland).
In 1993, during a debate in the UN Security Council, the UK representative stated:
The United Kingdom Government has been horrified at the continued evidence of massive breaches of international humanitarian law and human rights in the former Yugoslavia … [including] the deliberate obstruction of humanitarian relief convoys. 
United Kingdom, Statement before the UN Security Council, UN Doc. S/PV.3217, 25 May 1993, p. 17.
In 2008, a UK Minister of State, Foreign and Commonwealth Office, wrote to the House of Lords in response to a question concerning the lawfulness of the Israeli blockade of Gaza:
We have serious concerns about the Israeli restrictions on Gaza and the impact they have on the lives of Gazans. Although there is no permanent physical Israeli presence in Gaza, given the significant control that Israel has over Gaza’s borders, airspace and territorial waters, Israel retains obligations under the [1949] Fourth Geneva Convention as an occupying power. …The restrictions currently imposed on the passage of relief supplies are, as we see it, a disproportionate response to the security threat.
The extent of Israeli restrictions, and the threat to Israel from militants in Gaza, varies constantly. Rather than focus on whether the restrictions at any given time amount to collective punishment, we have consistently pressed the Israeli Government to comply with their obligations under international law … This was the message my right honourable friend the Foreign Secretary delivered in his meetings with Israeli leaders during his recent visit to the region. 
United Kingdom, House of Lords, Written Answer by a Minister of State, Foreign and Commonwealth Office, Hansard, 26 November 2008, Vol. 705, Written Answers, col. WA320.
The UK Government Strategy on the Protection of Civilians in Armed Conflict (2010) states under the heading “Improving humanitarian access”:
Unfortunately, in many conflict affected countries humanitarian access is increasingly unsafe, delayed and otherwise restricted, leaving millions of vulnerable people deprived of life-saving protection and assistance. 
United Kingdom, Foreign and Commonwealth Office, Government Strategy on the Protection of Civilians in Armed Conflict, March 2010, p. 10.