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Trading 212 has boosted the rate on its cash Isa twice in the same day, hiking it all the way up to 4.67 per cent.

Providers at the top of our easy-access cash Isa rates table periodically kick off rate tussles and this appears to be a new skirmish, with Trading 212* topping the table.

Moneybox has boosted its cash Isa rate from 4.55 per cent to 4.65 per cent variable, which includes a 1.2 per cent bonus for 12 months.

Meanwhile Plum* has lifted its cash Isa rate from 4.48 per cent to 4.6 per cent variable, which includes a 2.06 per cent bonus for 12 months.

Not to be outdone, Trading 212's rate currently sits at the top of our cash Isa best-buy tables. This account also includes a fixed bonus, at 1.07 per cent for 12 months.

Keep in mind that Trading 212's promotional rate only applies to funds deposited in the current tax year, so transfers of contributions made in previous tax years will receive the standard 3.6 per cent rate. 

> Find out more about opening a cash Isa at Trading 212*

Both Trading 212 and Plum offer flexible Isas, which means you can withdraw money and replace it in the same tax year without reducing your Isa allowance.

You also only need £1 to open an account with these providers.

Trading 212's* normal, non-boosted 3.6 per cent rate is higher than Plum's, which plummets after 12 months to 2.54 per cent.

This is a good reminder to keep on top of the rate you're receiving, especially when taking up a short-term boost.

If you're keen to transfer an Isa, Plum* is offering a lower 4 per cent variable rate, which includes a 1.46 per cent boost for 12 months.

This could work out better than Trading 212 when transferring funds from previous tax years, because those funds would receive Trading 212's normal 3.6 per cent rate.

But you can open an Isa with Trading 212 and pay new money in to get its best rate, while transferring older pots to Plum or elsewhere. 

When it comes to Moneybox, the savings and investing platform is offering a good rate of 4.65 per cent, which includes the short-term 1.2 per cent bonus. 

There isn't quite the same cliff-edge as at Plum, as the underlying rate is set at 3.45 per cent.

However, if you withdraw and replace your money, your Isa allowance will be hit because Moneybox doesn't offer a flexible Isa.

It also has more catches, with a higher minimum deposit of £500, and you must keep your balance at this level and make less than four withdrawals a year, otherwise your rate will nosedive to 0.75 per cent.

Moneybox does have a less restrictive open-access cash Isa with no withdrawal restrictions and a £1 minimum deposit, but the rate is lower at 3.8 per cent including a 0.55 per cent boost for 12 months.