Ms English said the job "became increasingly untenable to continue. As time progressed I continued to be marginalised.
She said she phoned Lord Sugar in May 2011 and asked if she could meet him but claims "he made it abundantly clear that he didn't want to see me."
She said she told Lord Sugar: "I have tried so hard for so long and it's not working. I'm an overpaid lackey at Viglen. My pride would not allow me to continue doing it."
Ms English said Lord Sugar then offered her a role in another company which she started in June 2011.
She said Lord Sugar told her that he had given her the second role because he did not want to damage the integrity of The Apprentice or the BBC, or to arm his own public image.
The tribunal continues.
Entrepreneur Lord Sugar has accused a former winner of his TV series The Apprentice of being a liar and attempting to blackmail him.
Lord Sugar condemned "claim culture" today as he accused a winner of his TV show The Apprentice of lying.