Speculation that Harry Styles is to quit One Direction is mounting after the 20-year-old appears to have taken another step towards distancing himself from his band mates.

The singer is believed to have set up his own business interests, separate from the band.

According to the Daily Mail, Styles has instructed Irish accountant Alan McEvoy to set up a new company called HSA Publishing Ltd, with just himself and McEvoy as directors.

McEvoy created 1D Media Limited after the band first came to prominence. Niall Horan, Zayn Malik, Liam Payne, Louis Tomlinson and Styles are all directors, each with a 20 per cent share in the concern.

Described as the most professional member of the band, Styles has been spotted recording and writing solo tracks.

His representatives maintain that there are no such plans for the teen heart-throb to go solo.

"There are no plans for Harry to release any solo music at this time, any writing that he is doing is for potential One Direction songs," a rep for One Direction told E! News on July 1.

"It's common knowledge that the boys write separately and bring to each other for the album."

But, as the most popular member of the band, he is predicted to be the most likely of the five to go it alone.

Music industry executives are said to be honing in on the star, who they predict will 'do a Robbie Williams' and leave at the height of his fame to pursue a solo career.

The recent controversy, sparked by video footage allegedly showing Zayn Malik and Louis Tomlinson smoking marijuana, is also rumoured to have created tensions between the band mates, with Styles said to be "livid" at the pair for being so irresponsible.

A 1D spokesman confirmed that Styles's new firm had been set up in agreement with other members of the band.

The band have a five-album deal and their fifth, a greatest hits record, is expected this year.

One Direction is currently on their Where We Are world tour.