Incentive Being Held By Employer If I Quit The Job

I am employed in a BPO as a customer service representative. Our company is an outsourcing company offering customer service to a UK based client. Our client recently sanctioned £250 bonus to employees with a year or more tenurity.I have been employed for the past 3 years and have been the top performer throughout my term..my employer have announced that if any body quits the company after receiving the bonus then this amount will be debited from their FnF settle.so to avoid this they are asking us not to quit the company atleast for the next 4 months..is this fair?? does my company have the right to do than??
I am looking to quit the company and willing to complete the formalities as per the company norms but I'm being exploited and threatened by my company that I if I take the bonus and quit they will deduct that amount from my fnf...
please advise what action should I take against my employer???

The company cannot deduct the bonus which they have already paid to you if you leave the service. Company does not have any such legal right to do that.
However, try to serve the notice period, if any, as per the appointment letter in order to avoid complications during full and final settlement.
Please check my labour law blog at www.labourlawhub.com

This is a performance bonus,mthat is not covered under the bonus act.
So the Company is free to put its terms.
However, they can not deduct that money from your PF, you don't have gratuity, so where will,they recover it from ?

May be the employer is free to put terms, but not absurd terms.

The terms are not absurd.
Bonus is being given to those who are willing to work for st least 4 months more.
If they were smart,mother would actually release the bonus after 4 months, but announce it now.

There is a wide difference between the incentive and bonus. So, at first, you should be clear about it. Bonus is linked with productivity of the company while incentive is given for performance of individual employees and to keep them motivated, as a measure to buy loyalty of the employees.