Attwood saw himself as the representative of the Birmingham 'industrious' classes: businessmen, masters and skilled workers in the small-scale industries of the Midlands. In January 1830 he founded the Birmingham Political Union, regarded as the political organisation most effective in exerting pressure on the government for passage of the Reform Bill of 1832. Attwood formed the BPU because of widespread economic distress, particularly after 1826.
Through its action, working-class protest was strengthened by middle-class agitation for parliamentary reform to secure currency reform. The union's structure and methods were applied in many parts of the country. After passage of the Reform Bill, Attwood was elected a Member of Parliament for Birmingham in 1832, sitting until 1839.
Attwood died on 6th March 1856 at Great Malvern, Worcestershire.