The short answer is no. Many contractors believe this is the case and many companies advertise that they can 'maximise your take home pay'.
However, the reality is that the tax you have to pay is determined by UK tax rules and your individual circumstances (your income sources, employment status / business structure and expenses genuinely incurred).
Whilst it's true that poor advice from an inexperienced accountant could lead to you missing out on opportunities to save tax, or not being set up in the most tax-advantageous way, ultimately your accountant has no influence over how much tax you should pay. Once they have correctly advised you of the standard ways, accepted by HMRC, in which you can plan your affairs to legitimately optimise your tax position, they can't make any further difference. Any specialist contractor accountant should know what advice to give in this area.
In the case of umbrella companies, this is even more true. If you're working through an umbrella company, by definition you are an employee and should be taxed accordingly, under PAYE, and also pay national insurance, the rules and rates for which are fixed by HMRC and the government, not your umbrella provider. If they are not deducting these prescribed rates of tax and NI, they must be using some other form of tax-avoidance scheme, which is very risky for you as an employee. If you have a genuine, robust over-arching contract with your umbrella company and an assignment that is going to last for less than two years, it's true that you can normally claim certain travel expenses... but you have to have actually incurred them in the first place and ultimately be able to prove as such. Whatever ' HMRC approved dispensations' an umbrella company has, it has to abide by the same rules as everyone else in terms of what is claimed and there are no 'round sum' claims available, unless expenses are genuinely being incurred by you. No umbrella company can deliver a higher take home pay than another, for the same set of circumstances, if they are operating compliantly under PAYE, and anything else is risky for you. The basic rate of UK income tax alone, under PAYE, is 20% (for all income above £9,440 pa) and that excludes national insurance, so offers of 80% plus, or even 90% plus take home pay, after paying the umbrella company's fees, are unlikely to be sustainable, or will rely on you having incurred significant expenses from your own pocket, or are likely to come with risk of investigation and potentially substantial, retrospective tax bills, interest and penalties.
Furthermore, no company can know or give you an accurate view of what your take home percentage will be, without knowing your exact circumstances and what expenses you will actually incur and any percentages claimed are likely to include some pretty 'helpful' assumptions on these areas, that may prove unfounded when your pay is actually calculated. There's no real harm in this as long as they disclose how they calculate the take home pay and what assumptions they use, but you should read the small print and be aware that these percentages may not apply to your specific circumstances.
When choosing an accountant or umbrella provider therefore, we recommend you look for one that is experienced in advising contractors and freelance professionals, offers a guarantee of great customer service and employs a systemised approach to ensure all tax planning opportunities are maximised, in a fully compliant way. Look for good customer service, quality, unbiased advice and value for money, not a 'too good to be true' take home pay slogan, which is unlikely to hold water and will be disappointing when you get your first payslip, dividend or tax bill... or worse still, may lead to serious trouble down the line with HMRC, particularly in the current anti-tax avoidance climate.