Jamie Spears has been his daughter's legal guardian for 12 years, due to concerns about her mental health.

Ms Spears' lawyer said the pop star was "afraid" of him, and that she would not perform so long as he remained in the role.

Her father's lawyer argued that he always acted in the best interests of his daughter.

A judge said she would consider future appeals for his dismissal or outright removal.

In the meantime, at the request of Ms Spears, financial company Bessemer Trust has been appointed as a co-conservator.

During a hearing on Tuesday, Ms Spears' lawyer, Samuel Ingham, said she and her father have no "viable working relationship" and have not spoken in a "long while".

But Vivian Thoreen, Jamie Spears' lawyer, argued that the reason they hadn't spoken was because Mr Ingham had advised Ms Spears against it.

Ms Thoreen also defended Mr Spears' record as conservator. When he assumed the role, Ms Spears was fighting tens of millions of dollars in lawsuits. But under his guidance, Ms Thoreen said her business operation was now worth $60m (£45m).

The legal battle is taking place against the backdrop of the "Free Britney" movement - a group of fans who believe Ms Spears is being kept prisoner by her father and others.

Britney Spears has not controlled her financial affairs or many of her career decisions since 2008 under the court-enacted agreement.

A conservatorship is usually granted for individuals who are unable to make their own decisions, like those with dementia or other mental illnesses.

Essentially, for the last dozen years, her father and attorney have managed her assets and personal life - including being able to restrict her visitors and communicate with doctors about her treatment.

The star began behaving erratically in 2007 after her divorce from Kevin Federline, and she lost custody of their two children, although she has frequent visits.

Her alleged mental breakdowns took place in the public eye. She made headlines for shaving her head and was photographed hitting a paparazzo's car with an umbrella, and went to rehab facilities several times.

She was placed in psychiatric care after refusing to surrender her sons in a stand-off with the police, and the conservatorship was put in place in early 2008.

In the years under the conservatorship, she has released four albums, completed a four-year Las Vegas residency, and served as a judge on The X Factor.

Tuesday's hearing took place against the backdrop of the #FreeBritney movement, an organisation of fans who believe Spears is being kept prisoner against her will.

Some in the movement say Spears sends coded messages about her captivity through her social media accounts.

The star recently responded to their concern in a video, saying she was doing "fine".

"I know that there have been a lot of comments and a lot of people saying a lot of different things about me, but I just want to let you guys know that I am fine," she said. "I'm the happiest I've ever been in my life."

Following the court hearing, Britney posted a vintage photograph of children playing in the street, captioned: "Keep jumping towards your dreams".

Some interpreted it as a cryptic comment on the court case. "Love you, your freedom is coming," wrote one fan in the comments.

"Keep jumping baby," added another. "I love you so much, we're here for you and we'll get through this!"

Britney Spears' mother, and James's ex-wife, Lynne Spears was allowed to take part in the hearing as an interested party.

In a statement released through her lawyer, she said her daughter should not be forced to obey her father's demands, calling their relationship "toxic."

"It has broken Lynne's heart that things have come to this point," Gladstone N Jones, said.

Jones added that Lynne Spears has no ill will towards James, but thinks it's "time to start fresh" and remove him.

"Contentiousness is not uncommon in families," Jones said, "but this is not a usual family."