Labour party members attending their conference in Brighton this weekend will be welcomed by a familiar face.

The Green Party has paid for a digital advert which makes the case Brighton Pavilion MP Caroline Lucas is the only person offering “real opposition” in parliament It will be on display in Queen’s Road, Brighton – the street which many of the 10,000 delegates arriving by train will travel down to reach the conference venues and hotels.

The ad starts with a check list, against a red backdrop, reading: “Saving the NHS, Fighting Austerity, Railways in Public Hands, Scrapping Trident.”

As the screen turns green, the billboard says “Brought to you by the Green Party.”

The final screen displays a photo of Caroline Lucas MP and reads: “Welcome to Brighton – Home of the True Opposition in Parliament. p.s. Labour is down the hill on the right”.

Rob Shepherd, chairman of Brighton and Hove Green Party, said: “We wanted to remind them there’s an MP already fighting for these causes in Parliament.

“It would be great to see Labour members using their conference to encourage Ed Miliband to follow Caroline’s lead on standing up for these causes, and bring together a powerful coalition to reverse the consensus that austerity and privatisation are the only game in town.”

Local Conservative councillors however questioned the use of the poster claiming that a condition for the billboard’s original permission insisted that it was not used for political ends.

Councillor Ken Norman said: “I remember when the original planning permission was granted, it was agreed political advertising couldn’t be on it because the groups that operate from that building are commissioned by the council and the council should be politically-neutral.”

On Saturday Lucas tweeted how she was ‘enjoying response to our (slightly mischievous) billboard welcoming Lab delegates to #Brighton’.