In January, Central Bedfordshire Council approved its own full planning application for the scheme which is proposed for a 69-hectare area of land to the north of Luton, between the M1 and the A6 roads.
A planning committee report said the application site is "entirely within the green belt" while a 1.6km central section "falls within the Chilterns Area of Outstanding Natural Beauty (AONB) and the Chilterns National Character Area".
However, planners advised that "very special circumstances" had been demonstrated, including the scheme's economic and social benefits, which would outweigh the harm to the openness of the green belt, and that "substantial public benefits" would outweigh any harm to the landscape and the AONB.
In February, Luton Council's executive agreed to proceed with a judicial review (JR) against Central Bedfordshire Council's decision to approve the application.
The council said that its key reason for pursuing a JR was to delay a decision so that inspectors examining Central Bedfordshire's local plan "can view the scheme and make sure [the council] has fully considered the potential impact of the proposed development on Luton residents and businesses".
Paul Castleman, Luton's portfolio holder for planning, said: "Central Bedfordshire Local Plan examination inspectors questioned whether a link road was needed. The inspectors' letters have not been properly considered in determining the planning application. Therefore we have no option other than to proceed with a JR."
However, the High Court has now declined to allow the case to proceed to a full JR.
A spokeswoman for Luton Council said: "We were disappointed to receive the news that our application for a judicial review against Central Bedfordshire Council's decision to grant permission for the M1-A6 link road had been refused.
"Prior to seeking a JR, we had made four objections to the planning application and spoken at the planning committee meetings.
"We also wrote to the secretary of state for housing, communities and local government requesting that they call-in the M1-A6 planning application for his determination. However, the secretary of state declined to call in the application.
"We do not intend to challenge the decision."