The minority of the Free Church, which had refused to join the union, quickly tested its legality.
However, the case was lost in the Court of Session, where Lord Low (upheld by the second division) held that the Assembly of original Free Church had a right, within limits, to change its position.
An appeal to House of Lords, (not delivered until 1 August 1904 due to a judicial death), reversed the Court of Session's decision (by a majority of 5–2), and found the minority entitled to the assets of the Free Church.
A convocation of the UF Church, held on 15 December, decided that the union should proceed, and resolved to pursue every lawful means to restore their assets.
They concluded, however, that the Free Church was in many respects unable to carry out the purposes of the trusts, which, under the ruling of the House of Lords, was a condition of their holding the property.
It combined an acceptance of the findings of contemporary science, and the more moderate results of higher criticism with commitment to evangelism and missions.
The UFC's approach to doctrinal conformity was fairly liberal for a Presbyterian denomination at the time.
In its 1906 Act Anent Spiritual Independence of the Church, its General Assembly asserted the power to modify or define its Subordinate standard (the Westminster Confession) and its laws.
Although its subordinate standard remained, ministers and elders were asked to state their belief in "the doctrine of this Church, set forth in the Confession of Faith".
[citation needed] The UFC had three divinity halls, at Glasgow, Edinburgh and Aberdeen, served by 17 professors and five lecturers.
These measures satisfied the majority of the UFC that the Church-state entanglement of the Church of Scotland, which had been the cause of the Disruption of 1843 had at last ended.
In 1929, the merger with the Church of Scotland largely reversed the Disruption of 1843 and reunited much of Scottish Presbyterianism.
On 2 October 1929, at an assembly at the Industrial Hall on Annandale Street off Leith Walk in Edinburgh, the two churches merged.
UFC members increased slightly during the 1930s, to a peak of 23,000 by 1939, but it never regained anywhere near the numbers it had had prior to the union with the Church of Scotland.
The General Assembly of the United Free Church of Scotland meets annually, beginning on the Wednesday after the first Sunday in June, and lasting until the Friday.
Since 2008, they have committed to having the General Assembly in a central location, meeting in the Salutation Hotel, Perth.