[2] By early 1917 German submarines made special efforts to attack petroleum tankers.
The instigation of the convoy system, with merchant shipping protected by Naval vessels, improved the supply of petroleum.
On 22 May 1917 the War Cabinet instructed Walter Long, the Secretary of State for the Colonies, to examine the whole question of petroleum supplies.
The Executive's remit was to ensure that all military and naval services had adequate supplies of oil, to address issues of general policy, and to co-ordinate those Government departments with an interest in petroleum.
[1][3] The independent Petroleum Executive was retained for a few years, but in 1922 it was retrenched into the Board of Trade as a cost cutting measure.