Class, women and the peaky blinders
I've been thinking a lot about how peaky blinders is a show intimately concerned with class and its seemingly inescapable boundaries. I think one of the most interesting ways that Tommy's obsession with class - and specifically, his singular ambition to move up a class - can be analysed is through the women he has relationships with.
Grace actually kinda operates outside of class lines as a spy, and though Tommy doesn't know that she is one, he's drawn to the fact that he can't quite quantify her. He's constantly trying to analyse her and assess her and understand her (see: the church scene where he jumps to the conclusion that she's simply a catholic girl who ran away from home and tries to hide it) and he's never quite able to figure out where she lies. Spies don't belong to one class, they move between them depending on what their goals are. When he finds out the truth, he can't really hate her because she achieves what he wants to achieve - seamless integration into a world that is not her own. Grace is able to fit into Tommy's life, but she also fits into the upper class background she's revealed to have. Where things go wrong is when Tommy tries to live the upper class life without adapting his behaviour (I think Polly says at one point that this new life they have is too much too fast, which I take to also apply to the fact they've tried to barrel into the upper class too quickly and it is unsustainable.) Grace dies when Tommy begins to court members of the monarchy - arguably the highest of all the classes.
Then there's May Carleton. May is a member of the upper class that Tommy aspires to, but as he continually seems to be confronted with throughout the show, the upper classes will never really accept him and it's a world he can't really penetrate (he says as much to Ada in the last episode of season three). That's why his relationship with May is never truly able to take off - on a level, Tommy knows that this world is not for him, and theres something about it that makes him uncomfortable and so he doesn't really try to push their relationship into becoming anything. Sure, he goes back to her at different points and they philosophise and sleep together but that's because Tommy's ambition is to be part of her world and he has to kind of repeatedly keep checking it he's any closer to it, if *now* is finally the time he can be with someone like May. But it never is. Inevitably, his relationship with May has to fizzle out.
The duchess Tatiana hits upon his problem as soon as she meets Tommy. She tells him that he acts like (to roughly paraphrase) "a boy who broke into the house through the basement". Even though he has the money and the big house and the connections he is still uncomfortable; he doesn't see himself as a true member of this new class he's in. He sleeps with Tatiana and things implode almost immediately afterwards as she starts running around his house with a loaded gun and playing Russian roulette. This woman, this duchess, is of the highest class Tommy has ever encountered and their relationship is short lived and untenable. It is chaotic because again, Tommy does not actually feel comfortable the further up in the class scale he goes. She reads him immediately and he is RATTLED - and with that analysis she pushes him back into the class boundaries he fought to escape. He becomes again the working class birmingham man who can't go higher.
Then there's Lizzie. She started from the same class as Tommy and has arguably travelled up with him which is why she's the woman that Tommy keeps turning to for comfort. She understands what it is to struggle and be looked down upon but she also knows what it means to try and pull yourself. She went from a prostitute to an assistant to essentially an executive secretary to a the wife of an MP. She knows the sides of Tommy that are working class Small Heath but she also knows the side that aspires to more. Regardless of whether he actually loves her, it's easy for Tommy to turn to her for comfort because not only does she know him, he knows *her* and he knows that there's no class boundary that she can achieve/has achieved without him or can kick him out of, unlike May (and to an extent, Grace) and Tatiana.
To briefly mention Jessie Eden, her whole character is about getting rid of class boundaries, or at least significantly reducing them. While Tommy sympathises with socialism at first, or at least a little as he claims to want similar things, getting rid of class boundaries would actually be terrible for him. His whole character is that he is ambitious and he wants to transcend his position and he can't do that if there's no "up", if there's nowhere for him to rise. So Jessie actually presents a bit of a moral dilemma for him - his personal political conscience versus his own ambition.
The women he surrounds himself with say a lot about his state of mind and ambition at the time, which is very smart or Stephen Knight and why this is one of the best shows on tv right now.