Some, including George Galloway and Craig Murray, believe Cross is not an individual, but an organized cell.   There are several divergent hypotheses, many of which are in line with long standing criticism that Wikipedia is vulnerable to use as an instrument of soft power by organized individuals who know how to format a reference.   
Cross has been an active English Wikipedia editor for 15 years. He often edits content related to the era of Iraq War and other subjects related to controversial political events. He is a person that is pro War on Terror.   He has also made edits to Former hedge-fund manager and Iraq war supporter Oliver Kamm, and right-wing author Melanie Phillips. 
From 2013 to 2018, Cross made Wikipedia edits every single day. He had a streak of 1,721 consecutive days of editing. As of 19 May 2018, he had made 133,706 total edits to Wikpedia, of which 34% (45,897) were to BLP (biographies of living persons). 
Disputed editing pattern
In 2018, Cross was accused of biased editing on Wikipedia. Sources have faulted him with using his knowledge of Wikipedia's guidelines to contribute added weight for his particular point of view. This acquired savvy allows Cross to protect BLPs of folks he likes, and to defend the addition of negative publicity into the BLPs of those he does not. 
Cross has edited pages of British politician George Galloway, as well as Matthew Gordon Banks, Nafeez Ahmed, Tim Hayward, Jeremy Corbyn, and media analysis group Media Lens.   He has also removed controversial information on Wikipedia pages for people whose politics he likes, although that has been properly cited.   In short, he's quite skilled at wikicraft and gatekeeping / edit-warring.
On February 7, 2016, former UK ambassador Craig Murray published an article calling out journalist Oliver Kamm for publishing what he called a lie about him. On the next day, Murray realized that his Wikipedia page had come under what he called an "obsessive attack": 
[...] somebody called Philip Cross [...] made an astonishing 107 changes over the course of the next three days. Many were very minor, but the overall effect was undoubtedly derogatory. He even removed my photo on the extraordinary grounds that it was “not typical” of me.
Cross has been open about his point of view on Twitter,  where he is often antagonistic towards the people whose Wikipedia pages he "edits". Tension began to brew when Cross was accused of paying special attention to a cluster of Wikipedia pages. 
Pundits like Galloway, academic Tim Hayward, opposition leader Jeremy Corbyn, and ex-UK ambassador to Uzbekistan Craig Murray have shown public disapproval of their Wikipedia edits and disappointment at how Wikipedia had not taken any actions to prevent such malicious editing. George Galloway offered a reward to see Cross unmasked.  Subsesequently, Mr. Galloway stated that the reward had been claimed, that he was aware of Cross' identity and believed the person behind the account had been manipulated. 
Several journalists, including Neil Clark, tweeted at Wikipedia asking for an explanation and demanding an investigation into the harassment of anti-war dissidents. This tendency was similarly observed in 2016 concerning the BLP pages for the Green presidential and vice-presidential candidate. Shortly after Cross was banned from the George Galloway entry, a familiar name in the American Politics moshpit picked up the slack and gathered attention by adding strategic section titles and cherry-picked quotes to the same entry.  Individual cells are fungible .
Wikipedia co-founder Jimmy Wales dismissed the complaints made about Cross as "risible".  The WMF responded to BBC inquiries to state that they had no control whatsoever over content disputes.  The WMF has, however, been doing a great deal of work on "conduct" issues.   The new techniques and technologies developed from this investment into resolving "conduct" issues (finer-grained page-level auto-blocks)  will likely spill over into "content" issues.
Already, in this case, one Wikipedian who got involved in a discussion about Philip Cross was threatened with a block by NeilN.  Another -- who took Philip Cross to 8RR trying to add an article from CounterPunch for balance on one of the articles Cross was stewarding -- was, in fact, blocked by NeilN. Despite being well over the "wiki" limit himself, Cross was not worried or warned about their role in that keyboard battle. It was over the use of a forbidden publication as a source for the official name of a working group. 
On June 8th, an Arbitration Committee case was opened.
Cross is a jazz and drama enthusiast.