The controversial group behind several bitcoin 'stress tests' has confirmed it will push ahead with its biggest experiment to date.

Speaking to CoinDesk, CoinWallet COO James Wilson said the test – which could reportedly cause a 30-day backlog of transactions – would be executed at 10am Thursday (GMT) next week.

The mysterious group, which sees its work as a drastic but necessary demonstration of Bitcoin XT's need, has been criticised by some users for "bullying" a live network worth several billion dollars.

Its first test in June, which aimed to fill blocks with 105 BTC broken into thousands of small transactions, reached just 15% of its 200MB goal before its servers crashed.

Although Wilson did not provide any specifics on next week's test, he did take credit for yesterday's network disruption – an apparent trial run which saw unconfirmed transactions on the network pile up to 50MB.

He said the group paid five times the standard fee – 0.0005 BTC per KB – to give its transactions priority on the network and "leave others waiting". Not all miners took the bait however, with some disregarding CoinWallet's transactions despite their higher fees. Wilson, who framed these actions as a form of censorship, said:

The tests come at a highly-charged time in bitcoin's development. Following the release of Bitcoin XT, the currency's major developers and contributors have been unable to reach a consensus on how bitcoin should be scaled – and what it should sacrifice in the process – as it approaches its so-called 'capacity cliff'.

While Jeff Garzik's BIP 100 proposal has seen increased support from bitcoin's biggest miners, wallets and other consumer services are still behind BIP 101, which grants miners less decision-making power. A workshop on the issue is scheduled in Montreal next week, two days after CoinWallet's test.