Born in London and schooled on the island of Guernsey, Roberts initially followed his father into the merchant marine, and after briefly living in Queensland he moved to Port Pirie, South Australia.

In late 1899, he crossed the floor and contributed to the defeat of the ministry of Charles Kingston, attracting sharp criticism from some parts of the ULP.

In December, Roberts, considering the fighting almost over, asked for and received permission to return home, and resumed his seat in the assembly.

Post-Federation, Roberts helped raise a unit of the Australian Commonwealth Horse and served with it as a captain in South Africa in 1902.

He retained his seat at the 1913 federal election, but soon after a fierce parliamentary debate on 2 December 1913 he collapsed and died from a heart condition.

The loss of Roberts – considered a highly capable and up-and-coming member of the ULP – was felt intensely by his political comrades, along with his fire, energy and enthusiasm.

In 1917 a monument was erected over his grave at West Terrace Cemetery in Adelaide, which The Advertiser newspaper described as "emblematic of the untimely end to [his] brilliant career".

Described in his entry in the Australian Dictionary of Biography as "[a] radical with exceptional abilities as an orator and organi[s]er",[1] Roberts was closely involved in the formation of a local workingmen's association, becoming its inaugural secretary.

[1][2] Undeterred, Roberts contested the same seat in the 1896 election as a United Labor Party (ULP) candidate, and was successful, coming second with 30.8 per cent of the votes, after the incumbent independent Alfred Catt.

[6] The premier of South Australia, Charles Kingston, had been obsessed for a long period with reducing the ability of the South Australian Legislative Council – the colony's upper house – to amend or reject legislation, but his reforms[7] – aimed at widening the franchise to all households rather than a set amount of property value[8] – were repeatedly voted down by its members.

[11][12] Although Roberts initially opposed the sending of South Australian colonial troops to the Second Boer War in 1899 on the grounds of cost and necessity,[13] combined with his impression that it was based on sentiment and not a true spirit of loyalty,[12] his position altered in response to British defeats, and in early 1900 he volunteered for the 4th Imperial Bushmen's Contingent raised from South Australia, and was commissioned as a lieutenant.

[1] At his farewell, he stated that he had volunteered to show solidarity with the mainly British uitlander migrant workers in the Boer republics, to broaden his experience and strengthen himself for political battles to come.

[12] The contingent, which consisted of two mounted squadrons commanded by Lieutenant Colonel James Rowell, embarked on the transport Manhattan at Port Adelaide on 1 May 1900.

[15] Attached to a battalion of imperial yeomanry commanded by British Colonel Arthur Montagu Brookfield supported by some artillery, the regiment escorted a convoy drawn by steam tractors, leaving Lindley on 23 June.

On 2 July Brookfield's column joined the command of Major General Arthur Paget for operations against the Boer commandoes led by Christiaan de Wet between Lindley and Bethlehem, also located in the Orange Free State.

Without waiting for the rest of the squadron, a dozen men led by Lieutenant Edwin Leane responded immediately and charged.

De Wet and 2,000 of his troops escaped north,[17] and the regiment pursued them to the Reitzburg hills as part of a force under Brigadier General Robert Broadwood.

[15] In the latter action, the regiment and some irregulars caught up with some flour-laden wagons of de Wet's rearguard and the Boers struck back to protect the precious supplies, killing four Australians.

Under Broadwood's command the regiment continued to pursue de Wet into the Transvaal, but by that point half of the South Australians were on foot, as their horses had died.

[18] This period included operations through Oliphant's Nek and the Magaliesberg Range, as well as the involvement of the regiment in the relief of the garrison at Elands River.

In December, given his view that the fighting was almost over, Roberts obtained permission from the British commander-in-chief to return home to his parliamentary and civic duties.

[22] Roberts was appointed as a lieutenant and as the battalion adjutant, and embarked at Melbourne on the transport St. Andrew on 12 January, disembarking at Durban on 10 March.

[29] This was followed by a "drive" by the entire force departing from Noitverwacht towards the Hartz River commencing on 7 May,[23] on a frontage 80 kilometres (50 mi) wide.

The drive was called to a halt at 15:00 on 11 May, when it reached the Kimberley to Mafeking railway line, and the commander-in-chief of British forces, Lord Kitchener, telegraphed his appreciation to Hamilton for the efforts of his troops.

It consists of a broken column of white Angaston marble, which was "emblematic of the untimely end to the brilliant career of the deceased legislator".

The monument was paid for by subscriptions received by the Labor Regulation League at their meetings, and was draped with the Union Jack and Australian flag before being unveiled by Roberts' successor in the federal seat of Adelaide, George Edwin Yates.

Although he confided in private that he suffered an "unconquerable inward nervousness",[1] Roberts was outstanding in parliamentary debates, highly skilled at quick and witty responses, and expressed himself readily and at length.