Councillor Gerald Vernon-Jackson said the decision would mean council lawyers would join the government in defending its decision to refuse permission for the £1.2bn interconnector proposed between the city and France.
'We will be in court to support the government and provide the local side to the case and demonstrate why it should not go ahead,' he said. 'It means that local issues will be fully considered by the court.
'It's really good news that we can have that say in opposing Aquind and represent all the views of people living in the city and reflects the hard work of our planning officers and lawyers to make sure it happens.’
The company’s bid to build land cables at Eastney, build an interconnector at Lovedean – and dig up large swatches of Portsmouth to connect the two – was turned down by the government in January, to much celebration.
The council has been set a deadline of July 25 for submitting paperwork required as part of the case and it is expected that a two-day hearing will take place 'several months' after that.
Business secretary Kwasi Kwarteng refused permission for the cable in January, saying the company had not properly considered 'more appropriate alternatives to the proposed route'.
It is estimated that the proposed 2GW cable could supply up to five per cent of the UK's energy needs but campaigners said the choice of route would lead to environmental 'destruction', years of 'traffic chaos' and 'made no sense'.
Opponents of the proposal include both the Labour MP for Portsmouth South, Stephen Morgan; the Conservative MP for Portsmouth North, Penny Mordaunt; and councillors of all political parties, as well as hundreds o people in Portsmouth who demonstrated and signed petitions against the scheme. The News, which was threatened with legal action several times by Aquind's lawyers for publishing stories about the interconnector scheme, also submitted a formal objection to the plan and was vocal in opposing it.
The decision has been welcomed by Stop Aquind campaign co-lead Viola Langley as 'great news'.
'I'm sure the council will make sure the views of local people are represented and I think that's a very important thing,' she said. 'There are a lot of issues with this project and interested party status will mean we can get a better understanding of what is happening.'
Concerns have also been raised about Aquind director Alexander Temerko who has donated more than £1m to the Conservative Party although his lawyers said he did not expect 'special treatment' in return.
The company confirmed in March that it had launched its judicial review challenging the decision. The judicial review only looks at the method used to come to a decision, not the decision itself. If Aquind wins, the whole planning process will start again.
In a statement made after Mr Kwarteng's decision was published, it said: 'We believe our application for a development consent order to be accurate and robust, and it has met all the requirements.'