Following the electoral triumph of Popular Front in February 1936 the Carlists were already set towards a violent overthrow of the republican regime.
However, the party executive was divided over the strategy to be adopted: Fal and his followers were gearing up for a stand-alone, exclusive Carlist rising, while another group preferred to join the military when they decide to move.
Tellería was firmly with the former.
Though he held some very vague preliminary talks with PNV on their participation in the plot, his key task was securing the military logistics.
As at the time he already owned the family tanning business and was recognized as “hombre de gran solvencia industrial en Guipúzcoa”, he was well suited for the role.
As early as in March he engineered a hoax, which sent metalworking products ordered for a bogus Bilbao customer shipped to Belgium, while 17 cases with hundreds of pistols and rifles, produced in the same Eibar plant and destined for Belgium, were delivered to Bilbao.
As the Carlist plan envisioned that at one point volunteers disguised as Guardia Civil would take control of key ministry offices in Madrid, Tellería took care of getting the uniforms ready.
Also in early March and as official supplier of leather products for the army, he managed to get hundreds of benemerita uniforms, produced on his order in Zaragoza, to be delivered to a Carlist depot in Madrid.
The republican security services got wind of the plan and stepped in; it did not take them long to identify Tellería as the key man behind the scheme.
He was arrested either in May or in early June; the Carlist plan had to be abandoned.

Following some shuttling between the arrests in Pamplona and Zaragoza, in late June Tellería was transferred to the Dirección General de Seguridad arrest in Madrid.
He claimed non-guilty and maintained that he believed the uniforms were intended for Spanish units in Africa.
Moved to the Modelo prison, it is there where he witnessed the July coup.
He survived the deadly fire of the prison of August 22-24 and then numerous repeated militia raids, usually ending with extraction of political prisoners and their ultimate execution.
When facing a makeshift revolutionary tribunal he posed as a Basque nationalist guilty of petty crimes.
The strategy apparently worked, as in late August he was set free.
He spent the next 3 months hiding at various friends and relatives in Madrid.
He assumed a false identity, made friends with some CNT militiamen, started to pose as one of them and – according to his own account – has even penetrated into their offices.
In early November he managed to arrange a travel to Valencia to obtain a passport, which in turn would enable him to return to Vascongadas.
The plan worked out and under the name of Múgica Tellería legally crossed to France.
He took the train to Saint-Jean-de-Luz, where he saw the Carlist regent, and by mid-November he returned to Antzuola, since late September controlled by the Carlists.
Following the electoral triumph of Popular Front in February 1936 the Carlists were already set towards a violent overthrow of the republican regime. However, the party executive was divided over the strategy to be adopted: Fal and his followers were gearing up for a stand-alone, exclusive Carlist rising, while another group preferred to join the military when they decide to move. Tellería was firmly with the former. Though he held some very vague preliminary talks with PNV on their participation in the plot, his key task was securing the military logistics. As at the time he already owned the family tanning business and was recognized as “hombre de gran solvencia industrial en Guipúzcoa”, he was well suited for the role. As early as in March he engineered a hoax, which sent metalworking products ordered for a bogus Bilbao customer shipped to Belgium, while 17 cases with hundreds of pistols and rifles, produced in the same Eibar plant and destined for Belgium, were delivered to Bilbao. As the Carlist plan envisioned that at one point volunteers disguised as Guardia Civil would take control of key ministry offices in Madrid, Tellería took care of getting the uniforms ready. Also in early March and as official supplier of leather products for the army, he managed to get hundreds of benemerita uniforms, produced on his order in Zaragoza, to be delivered to a Carlist depot in Madrid. The republican security services got wind of the plan and stepped in; it did not take them long to identify Tellería as the key man behind the scheme. He was arrested either in May or in early June; the Carlist plan had to be abandoned.
Following some shuttling between the arrests in Pamplona and Zaragoza, in late June Tellería was transferred to the Dirección General de Seguridad arrest in Madrid. He claimed non-guilty and maintained that he believed the uniforms were intended for Spanish units in Africa. Moved to the Modelo prison, it is there where he witnessed the July coup. He survived the deadly fire of the prison of August 22-24 and then numerous repeated militia raids, usually ending with extraction of political prisoners and their ultimate execution. When facing a makeshift revolutionary tribunal he posed as a Basque nationalist guilty of petty crimes. The strategy apparently worked, as in late August he was set free. He spent the next 3 months hiding at various friends and relatives in Madrid. He assumed a false identity, made friends with some CNT militiamen, started to pose as one of them and – according to his own account – has even penetrated into their offices. In early November he managed to arrange a travel to Valencia to obtain a passport, which in turn would enable him to return to Vascongadas. The plan worked out and under the name of Múgica Tellería legally crossed to France. He took the train to Saint-Jean-de-Luz, where he saw the Carlist regent, and by mid-November he returned to Antzuola, since late September controlled by the Carlists.
Agustín Tellería Mendizábal