Quote Originally Posted by northernladuk View Post
Are they obliged to do so when you request this service? I'd say no. It's not part of the contract and your engagement with them so it's a nice to have but if were them I wouldn't. You could ask if they would in individual case and the fact you've a long engagement so they may be flexible.
There is no contract, so you can't say it is not part of the contract. He's being asked to extend. Whether the agency legally can do it is something I doubt, but if they can, he can certainly ask to have it as part of the contract.

OP, if they need you that badly, simply say, "I was willing to take an inside IR35 contract for a limited time, but the taxes are too high. I can't even make pension payments without paying NI on it, and your employees don't have to pay NI on what you pay into their pensions, so I'm worse off than an employee when it comes to tax. Either you need to work with me to structure the contract and working practices to be outside IR35, or I need a 13.8% increase to cover the employer NI. Maybe you can get the agency to reduce their cut to help make up the difference." If they want to keep you on inside-IR35 terms, they should at least be willing to pay the employer NI.

If they restructure to outside, everything is straightforward. If they increase your rate, just make personal pension contributions out of post-tax funds. Sorted.

Be prepared for a counter-offer and know what is the minimum level you would accept. If they are fair, they'll consider it.