The former Labour prime minister said the Tory-led government at Westminster had repeatedly blundered by wrongly portraying the choice facing Scotland's voters as a contest between British and Scottish visions for the union.
"Breakaways often happen – or are at least hastened – through the mishandling of discontent," he writes in an essay for the Guardian published as the yes and no campaigns marked 100 days before the referendum on 18 September.
"From the catastrophic mistakes with America in the 1770s to the bloody transfers of power in Ireland, then India and Africa, Britain has never been very good at dealing with secessionist movements."
In one of the most significant attacks on Labour's allies in the pro-UK campaign, Brown claimed that UK ministers had failed to grasp that Scotland sees itself as a proud and distinctive nation – one of the few issues that yes and no campaigners agreed on, he said.
Unless Britain realised that Scotland needed more autonomy by "changing of its own volition" to help preserve the union as a secure multinational partnership, the UK faced the threat of even greater divisions and demands for a form of federalism.
In an unusually emotive essay linked to publication of a new book, My Scotland, Our Britain, Brown implied that this negative campaigning – a tactic used repeatedly by the pro-UK Better Together campaign, run by his former chancellor, Alistair Darling, had provoked many Scottish voters into backing a yes vote.
That air of blundering had been underlined, he said, by the UK government's "patronising" use of Lego figures eating pies, drinking Bovril and buying cheap holidays to illustrate the Treasury case that Scots would be £1,400 a year better off by voting no.
Brown said the no campaign had to make a far more positive case for the union and become far more sensitive to Scotland's views and its damaging experiences with globalisation, an argument that UK ministers had now begun to understand.
"Ministers forgot that it is only Scots who are voting in the referendum, that the Scottish voter's starting point is not going to be the greatness of Britain or the longevity of the union but their own needs and aspirations as Scots; and that the 'no' campaign will win only by presenting a Scottish vision of Scotland's future as a patriotic alternative to that of the SNP," he writes.
"Of course, the defence secretary [Phillip Hammond] was factually correct when he said that UK arms contracts would not come to an independent Scotland's shipyards.
"But instead of using the language of threats and ultimatums, a far better pro-union argument is to praise Scots defence workers for their unique contribution and support Scots who argue for pooling our resources for our mutual defence."
Speaking to political journalists at Westminster, Brown agreed it was "a good idea" that the prime minister should take part in a TV debate with Alex Salmond – a demand by the first minister that Cameron and Better Together have repeatedly rejected.
As the rival campaigns geared up for 100 days of intense campaigning, the lead pro-independence group, Yes Scotland, said 791,000 voters in Scotland had signed a declaration backing independence in September's referendum.
Blair Jenkins, its chief executive, said he was confident it would hit its goal of 1m signatures – a target first set by Alex Salmond more than two years ago – before referendum day. It was "an important target for us because it demonstrates the reach and the depth and strength of the campaign, and how many people we've got working for us," Jenkins said.
Now the figurehead of his party's official pro-UK campaign United with Labour, Brown's attacks mark a concerted attempt by Scottish Labour to detach itself from the Tory party in its drive to pull back votes from Labour supporters now supporting independence.
Some polls suggest more than 20% of Labour voters will chose yes at the referendum; others put that figure at under 15%. Independence campaigners are focusing heavily on Scottish dislike of the Tories and the Tory-led government in London to drive up support for independence.
But Brown's broadside also comes as other pro-UK sources have confirmed that Labour, the Tories and the Lib Dems are discussing a joint statement before the referendum pledging that a no vote will mean Scotland getting extra tax and political powers.
Described by one UK party source as a "renewal of vows", Alistair Darling, the chairman of Better Together, said that the commitment to more devolution from all three parties gave Scottish voters a clear choice.
"Now – with 100 days to go – the terms of trade have changed. And with it the ground has shifted under, and against, our nationalist opponents. For it is now clear that a no vote will bring more powers to Scotland within the UK," Darling told about 600 people at Better Together's launch of their summer campaign.
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