The associate director of the Institute for Fiscal Studies has said there's merit to Phillip Hammond's plans to raise National Insurance requirements for the self-employed.
The measure to raise NI payments by self-employed people up to 2% has proved to be controversial across both sides of the House of Commons.
Prime Minister Theresa May has said any debate on the planned change will come in the autumn, and promised that the Chancellor will listen to MPs' concerns in the interim.
Helen Miller, associate director at the Institute for Fiscal Studies, said we need to understand the context behind this change.
She said: "There's a really important context in this debate because currently the tax system is really unfair.
"If you're a self-employed person getting a tax break, that's great. But 85% of the country are employees, and people like us are getting penalties.
"I completely understand no one wants to pay higher taxes, but benefits expenses are still more generous for the self-employed compared to employees.
"There are employees out there traveling for work, doing long hours, staying away from home, and they still have those [same] issues as self-employed people.
"There's massive unfairness in the system, and it's right we try to close that down."