There is a thread running on the main rumors section but I will paste the relevant notam here where it states that even LHR based Airlines are being rationed.
They are looking at various options but this problem may be around for some time to come.
Here is the NOTAM.
Q)EGTT/QFULT/IV/NBO/A/000/999/5129N00028W005
FROM 06/01/30 12:24 TO 06/03/30 12:00 EST A0151/06
E)HEATHROW AIRPORT IS EXPERIENCING REDUCED DELIVERIES OF JET FUEL.
IN ORDER TO ENSURE CONTINUANCE OF OPS, THE ARRANGEMENTS AGREED IN THE
DRAFT HEATHROW FUEL CONTINGENCY PLAN (HFCP) WILL APPLY WIE.
THE SITUATION REMAINS UNDER CONSTANT REVIEW AND AS SUPPLIES AND
STOCKS CHANGE FURTHER CONSIDERATION WILL BE GIVEN TO THE OPERATIONAL
IMPACTS ON EACH AIRLINE.
ALL INBOUND ACFT WILL MAXIMISE TANKERING OPPORTUNITIES. IN ADDITION
TO TANKERING, FUEL RESTRICTIONS WILL ALSO APPLY.
USING THE HFCP, EACH CARRIER WILL, ON A DAILY BASIS, BE ALLOCATED A
PERCENTAGE OF THE PREVIOUS WEEKS TOTAL UPLIFT. THIS ALLOCATION CAN BE
USED AT AIRLINES DISCRETION.
ALL DEPARTING ACFT WILL RECEIVE FUEL, BUT ON A REDUCED BASIS -
(REFLECTING NORMAL CONTINGENCY PRACTICE WORLDWIDE). THE FOLLOWING
RESTRICTIONS APPLY:
NEW ALLOCATION FOR VISITING CARRIERS AT LHR WILL BE AS FOLLOWS:
FLTS UP TO 5 HR DURATION WILL RECEIVE 40 PER CENT OF NORMAL UPLIFT
FLTS OVER 5 HR DURATION WILL RECEIVE 70 PER CENT OF NORMAL UPLIFT
NEW ALLOCATION FOR BASE CARRIERS:
FLTS UP TO 5 HR DURATION WILL RECEIVE 55 PER CENT OF NORMAL UPLIFT
FLTS OVER 5 HR DURATION WILL RECEIVE 82 PER CENT OF NORMAL UPLIFT
CONSIDERATION WILL BE GIVEN TO AIRLINES THAT PREDOMINANTLY OPERATE
ACFT AT THE LIMIT OF THEIR RANGE. AIRLINES IN THIS CATEGORY SHOULD
CONTACT THE AIRSIDE BUSINESS RECOVERY TEAM ON 020 8745 7582 TO
ESTABLISH AN AGREEMENT.
THE SITUATION WILL BE MONITORED DAILY AND AIRLINES PERFORMANCE
MEASURED, AS THE FUEL SITUATION DEVELOPS THE ALLOWANCES MAY BE
ADJUSTED AND FURTHER NOTAM WILL BE ISSUED.